Area

http://www.lahc.edu/math/frankma.htm
Area
If we connect the two
ends of a rope that’s
resting flat in a plane,
we obtain a loop.
Area
If we connect the two
ends of a rope that’s
resting flat in a plane,
we obtain a loop.
The loop forms a
perimeter or border
that encloses an area, i.e. a surface in the plane.
Area
If we connect the two
ends of a rope that’s
resting flat in a plane,
we obtain a loop.
The loop forms a
perimeter or border
that encloses an area, i.e. a surface in the plane.
The word “area” also denotes the amount of surface
enclosed which is defined below.
Area
If we connect the two
ends of a rope that’s
resting flat in a plane,
we obtain a loop.
The loop forms a
perimeter or border
that encloses an area, i.e. a surface in the plane.
The word “area” also denotes the amount of surface
enclosed which is defined below.

1 in
1 in

1m
1m

1 mi

1 mi
Area
If we connect the two
ends of a rope that’s
resting flat in a plane,
we obtain a loop.
The loop forms a
perimeter or border
that encloses an area, i.e. a surface in the plane.
The word “area” also denotes the amount of surface
enclosed which is defined below.
If each side of a square is 1 unit, then we define the area of
the square to be 1 unit x 1 unit = 1 unit2, i.e. 1 square-unit.

1 in
1 in

1m
1m

1 mi

1 mi
Area
If we connect the two
ends of a rope that’s
resting flat in a plane,
we obtain a loop.
The loop forms a
perimeter or border
that encloses an area, i.e. a surface in the plane.
The word “area” also denotes the amount of surface
enclosed which is defined below.
If each side of a square is 1 unit, then we define the area of
the square to be 1 unit x 1 unit = 1 unit2, i.e. 1 square-unit.
Hence the areas of the following squares are:
1 in
1m
1 mi
1 in

1m

1 mi
Area
If we connect the two
ends of a rope that’s
resting flat in a plane,
we obtain a loop.
The loop forms a
perimeter or border
that encloses an area, i.e. a surface in the plane.
The word “area” also denotes the amount of surface
enclosed which is defined below.
If each side of a square is 1 unit, then we define the area of
the square to be 1 unit x 1 unit = 1 unit2, i.e. 1 square-unit.
Hence the areas of the following squares are:
1 in
1m
1 mi
1 in

1 in2

1 square-inch

1m

1 mi
Area
If we connect the two
ends of a rope that’s
resting flat in a plane,
we obtain a loop.
The loop forms a
perimeter or border
that encloses an area, i.e. a surface in the plane.
The word “area” also denotes the amount of surface
enclosed which is defined below.
If each side of a square is 1 unit, then we define the area of
the square to be 1 unit x 1 unit = 1 unit2, i.e. 1 square-unit.
Hence the areas of the following squares are:
1 in
1m
1 mi
1 in

1 in2

1 square-inch

1m

1 m2

1 square-meter

1 mi

1 mi2

1 square-mile
Area
A 2 mi x 3 mi rectangle may be cut into
six 1 x 1 squares so it covers an area of
2 x 3 = 6 mi2 (square miles).

3 mi
2 mi
Area
A 2 mi x 3 mi rectangle may be cut into
six 1 x 1 squares so it covers an area of
2 x 3 = 6 mi2 (square miles).

3 mi
2 mi

2x3
= 6 mi2
Area
A 2 mi x 3 mi rectangle may be cut into
2 mi
six 1 x 1 squares so it covers an area of
2 x 3 = 6 mi2 (square miles).
In general, given the rectangle with
height = h (units)
width* = w (units),
h
2).
then its area A = h x w (unit

* For our discussion, the “width” is the horizontal length.

3 mi
2x3
= 6 mi2
w
Area

3 mi

A 2 mi x 3 mi rectangle may be cut into
2x3
2 mi
six 1 x 1 squares so it covers an area of
= 6 mi2
2 x 3 = 6 mi2 (square miles).
In general, given the rectangle with
w
height = h (units)
width* = w (units),
h A = h x w (unit2)
then its area A = h x w (unit2).

* For our discussion, the “width” is the horizontal length.
Area

3 mi

A 2 mi x 3 mi rectangle may be cut into
2x3
2 mi
six 1 x 1 squares so it covers an area of
= 6 mi2
2 x 3 = 6 mi2 (square miles).
In general, given the rectangle with
w
height = h (units)
width* = w (units),
h A = h x w (unit2)
then its area A = h x w (unit2).
A square is a rectangle with four equal
sides s as shown.
s
s
A square

* For our discussion, the “width” is the horizontal length.
Area

3 mi

A 2 mi x 3 mi rectangle may be cut into
2x3
2 mi
six 1 x 1 squares so it covers an area of
= 6 mi2
2 x 3 = 6 mi2 (square miles).
In general, given the rectangle with
w
height = h (units)
width* = w (units),
h A = h x w (unit2)
then its area A = h x w (unit2).
A square is a rectangle with four equal
sides s as shown.
s
The perimeter of a square is s + s + s + s = 4s.
The area of a square is s*s = s2.
s
A square

* For our discussion, the “width” is the horizontal length.
Area

3 mi

A 2 mi x 3 mi rectangle may be cut into
2x3
2 mi
six 1 x 1 squares so it covers an area of
= 6 mi2
2 x 3 = 6 mi2 (square miles).
In general, given the rectangle with
w
height = h (units)
width* = w (units),
h A = h x w (unit2)
then its area A = h x w (unit2).
A square is a rectangle with four equal
sides s as shown.
s
The perimeter of a square is s + s + s + s = 4s.
The area of a square is s*s = s2.
s
So the perimeter of a 10 m x 10 m square is 40 m.
A square
2 = 100 m2.
and its area is 10

* For our discussion, the “width” is the horizontal length.
Area

3 mi

A 2 mi x 3 mi rectangle may be cut into
2x3
2 mi
six 1 x 1 squares so it covers an area of
= 6 mi2
2 x 3 = 6 mi2 (square miles).
In general, given the rectangle with
w
height = h (units)
width* = w (units),
h A = h x w (unit2)
then its area A = h x w (unit2).
A square is a rectangle with four equal
sides s as shown.
s
The perimeter of a square is s + s + s + s = 4s.
The area of a square is s*s = s2.
s
So the perimeter of a 10 m x 10 m square is 40 m.
A square
2 = 100 m2.
and its area is 10
s
An area with four equal sides in general is called
a rhombus (diamond shapes).
s
A rhombus

* For our discussion, the “width” is the horizontal length.
Area

3 mi

A 2 mi x 3 mi rectangle may be cut into
2x3
2 mi
six 1 x 1 squares so it covers an area of
= 6 mi2
2 x 3 = 6 mi2 (square miles).
In general, given the rectangle with
w
height = h (units)
width* = w (units),
h A = h x w (unit2)
then its area A = h x w (unit2).
A square is a rectangle with four equal
sides s as shown.
s
The perimeter of a square is s + s + s + s = 4s.
The area of a square is s*s = s2.
s
So the perimeter of a 10 m x 10 m square is 40 m.
A square
2 = 100 m2.
and its area is 10
s
An area with four equal sides in general is called
a rhombus (diamond shapes). The perimeter of
s
a rhombus is 4s, but its area depends on its shape.
A rhombus

* For our discussion, the “width” is the horizontal length.
Area
Example A. Find the area of the following
shape R. Assume the unit is meter.

4

4

R
12

12
Area
Example A. Find the area of the following
shape R. Assume the unit is meter.

4

4

R
12

12
Area
Example A. Find the area of the following
shape R. Assume the unit is meter.
There are two basic approaches.

4

4

R
12

12
Area
Example A. Find the area of the following
shape R. Assume the unit is meter.
There are two basic approaches.
I. We may view R as a
12 x 12 = 144 m2 square
with a 4 x 8 = 32 m2
corner removed.

8
4

R
12

12

4

4

4

R
12

12
Area
Example A. Find the area of the following
shape R. Assume the unit is meter.
There are two basic approaches.
I. We may view R as a
12 x 12 = 144 m2 square
with a 4 x 8 = 32 m2
corner removed.
Hence the area of R is
144 – 32
= 112 m2
8
4

R
12

12

4

4

4

R
12

12
Area
Example A. Find the area of the following
shape R. Assume the unit is meter.

4

R

There are two basic approaches.
12
12
I. We may view R as a
12 x 12 = 144 m2 square
Il. We may dissect R into two
2
with a 4 x 8 = 32 m
rectangles I and II as shown.
corner removed.
Hence the area of R is
144 – 32
= 112 m2
8

8
4

R
12

4
4

I
12

12

4

II
12

4
Area
Example A. Find the area of the following
shape R. Assume the unit is meter.

4

R

There are two basic approaches.
12
12
I. We may view R as a
12 x 12 = 144 m2 square
Il. We may dissect R into two
2
with a 4 x 8 = 32 m
rectangles I and II as shown.
corner removed.
Area of I is 12 x 8 = 96,
Hence the area of R is
area of II is 4 x 4 = 16.
144 – 32
= 112 m2
8

8
4

R
12

4
4

I
12

12

4

II
12

4
Area
Example A. Find the area of the following
shape R. Assume the unit is meter.

4

R

4

There are two basic approaches.
12
12
I. We may view R as a
12 x 12 = 144 m2 square
Il. We may dissect R into two
2
with a 4 x 8 = 32 m
rectangles I and II as shown.
corner removed.
Area of I is 12 x 8 = 96,
Hence the area of R is
area of II is 4 x 4 = 16.
144 – 32
The area of R is the sum of the
= 112 m2
two or 96 + 16 = 112 m2.
8

8
4

R
12

4
4

I
12

12

4

II
12
Area
Example A. Find the area of the following
shape R. Assume the unit is meter.

4

4

R

There are two basic approaches.
12
12
I. We may view R as a
12 x 12 = 144 m2 square
Il. We may dissect R into two
2
with a 4 x 8 = 32 m
rectangles I and II as shown.
corner removed.
Area of I is 12 x 8 = 96,
Hence the area of R is
area of II is 4 x 4 = 16.
144 – 32
The area of R is the sum of the
= 112 m2
two or 96 + 16 = 112 m2.
8
4

R
12

4
4

I
12

12

8

8

iii

4

II
12

12

4

4

iv

(We may also cut R
into iii and iv as shown here.)

12
Area
b. Find the area of the following shape R.
Let’s cut R into three rectangles
as shown.

2 ft
Area
b. Find the area of the following shape R.
Let’s cut R into three rectangles
as shown.

I

II
III

2 ft
Area
b. Find the area of the following shape R.
Let’s cut R into three rectangles
as shown.
Area of I is 2 x 2 = 4,

I

II
III

2 ft
Area
b. Find the area of the following shape R.
Let’s cut R into three rectangles
as shown.
Area of I is 2 x 2 = 4,
area of II is 2 x 6 = 12,

I

II
III

2 ft
Area
b. Find the area of the following shape R.
Let’s cut R into three rectangles
as shown.
Area of I is 2 x 2 = 4,
area of II is 2 x 6 = 12,
and area of III is 2 x 5 = 10.

I

II
III

2 ft
Area
b. Find the area of the following shape R.
Let’s cut R into three rectangles
as shown.
Area of I is 2 x 2 = 4,
area of II is 2 x 6 = 12,
and area of III is 2 x 5 = 10.
Hence the total area is 4 + 12 + 10 = 16 ft2.

I

II
III

2 ft
Area
b. Find the area of the following shape R.
Let’s cut R into three rectangles
as shown.
Area of I is 2 x 2 = 4,
area of II is 2 x 6 = 12,
and area of III is 2 x 5 = 10.
Hence the total area is 4 + 12 + 10 = 16 ft2.
c. Two rectangular walk-ways crosses each
other perpendicularly as shown. The larger
one is 25 ft x 6 ft and the smaller one is
20 ft x 4 ft. What is the total area they cover?

I

2 ft

II
III
20 ft
4 ft

25 ft

6 ft
Area
b. Find the area of the following shape R.
Let’s cut R into three rectangles
as shown.
Area of I is 2 x 2 = 4,
area of II is 2 x 6 = 12,
and area of III is 2 x 5 = 10.
Hence the total area is 4 + 12 + 10 = 16 ft2.
c. Two rectangular walk-ways crosses each
other perpendicularly as shown. The larger
one is 25 ft x 6 ft and the smaller one is
20 ft x 4 ft. What is the total area they cover?
The area of the larger strip is 25 x 6 = 150 ft2

I

2 ft

II
III
20 ft
4 ft

25 ft

6 ft
Area
b. Find the area of the following shape R.
Let’s cut R into three rectangles
as shown.
Area of I is 2 x 2 = 4,
area of II is 2 x 6 = 12,
and area of III is 2 x 5 = 10.
Hence the total area is 4 + 12 + 10 = 16 ft2.

I

2 ft

II
III
20 ft

c. Two rectangular walk-ways crosses each
other perpendicularly as shown. The larger
one is 25 ft x 6 ft and the smaller one is
20 ft x 4 ft. What is the total area they cover?
25 ft
2
The area of the larger strip is 25 x 6 = 150 ft
and the area of the smaller strip is 20 x 4 = 80 ft2.

4 ft

6 ft
Area
b. Find the area of the following shape R.
Let’s cut R into three rectangles
as shown.
Area of I is 2 x 2 = 4,
area of II is 2 x 6 = 12,
and area of III is 2 x 5 = 10.
Hence the total area is 4 + 12 + 10 = 16 ft2.

I

2 ft

II
III
20 ft

c. Two rectangular walk-ways crosses each
other perpendicularly as shown. The larger
one is 25 ft x 6 ft and the smaller one is
20 ft x 4 ft. What is the total area they cover?
25 ft
2
The area of the larger strip is 25 x 6 = 150 ft
and the area of the smaller strip is 20 x 4 = 80 ft2.
Their sum 150 + 80 = 230 includes the 4 ft x 6 ft (= 24 ft2)
rectangular overlap twice.

4 ft

6 ft
Area
b. Find the area of the following shape R.
Let’s cut R into three rectangles
as shown.
Area of I is 2 x 2 = 4,
area of II is 2 x 6 = 12,
and area of III is 2 x 5 = 10.
Hence the total area is 4 + 12 + 10 = 16 ft2.

I

2 ft

II
III
20 ft

c. Two rectangular walk-ways crosses each
other perpendicularly as shown. The larger
one is 25 ft x 6 ft and the smaller one is
20 ft x 4 ft. What is the total area they cover?
25 ft
2
The area of the larger strip is 25 x 6 = 150 ft
and the area of the smaller strip is 20 x 4 = 80 ft2.
Their sum 150 + 80 = 230 includes the 4 ft x 6 ft (= 24 ft2)
rectangular overlap twice. Hence the total area covered is
230 – 24 = 206 ft2.

4 ft

6 ft
Area
A parallelogram is a shape enclosed by two sets of parallel lines.

h
b
Area
A parallelogram is a shape enclosed by two sets of parallel lines.
By cutting and pasting, we may arrange a parallelogram into a
rectangle.

h
b
Area
A parallelogram is a shape enclosed by two sets of parallel lines.
By cutting and pasting, we may arrange a parallelogram into a
rectangle.

h
b
Area
A parallelogram is a shape enclosed by two sets of parallel lines.
By cutting and pasting, we may arrange a parallelogram into a
rectangle.

h

h
b

b
Area
A parallelogram is a shape enclosed by two sets of parallel lines.
By cutting and pasting, we may arrange a parallelogram into a
rectangle.

h

h
b

b

Hence the area of the parallelogram is A = b x h where
b = base and h = height.
Area
A parallelogram is a shape enclosed by two sets of parallel lines.
By cutting and pasting, we may arrange a parallelogram into a
rectangle.

h

h
b

b

Hence the area of the parallelogram is A = b x h where
b = base and h = height.

8 ft

12 ft
Area
A parallelogram is a shape enclosed by two sets of parallel lines.
By cutting and pasting, we may arrange a parallelogram into a
rectangle.

h

h
b

b

Hence the area of the parallelogram is A = b x h where
b = base and h = height.

8 ft

12 ft

8 ft

12 ft
Area
A parallelogram is a shape enclosed by two sets of parallel lines.
By cutting and pasting, we may arrange a parallelogram into a
rectangle.

h

h
b

b

Hence the area of the parallelogram is A = b x h where
b = base and h = height.

8 ft

12 ft

8 ft

8 ft

12 ft

12 ft
Area
A parallelogram is a shape enclosed by two sets of parallel lines.
By cutting and pasting, we may arrange a parallelogram into a
rectangle.

h

h
b

b

Hence the area of the parallelogram is A = b x h where
b = base and h = height.

8 ft

12 ft

8 ft

8 ft

12 ft

12 ft

8 ft

12 ft
Area
A parallelogram is a shape enclosed by two sets of parallel lines.
By cutting and pasting, we may arrange a parallelogram into a
rectangle.

h

h
b

b

Hence the area of the parallelogram is A = b x h where
b = base and h = height.
For example, the area of all
the parallelograms shown
8 ft
8 ft
12 ft
here is 8 x 12 = 96 ft2,
12 ft
so they are the same size.
8 ft

12 ft

8 ft

12 ft
Area
A triangle is half of a parallelogram.
Area
A triangle is half of a parallelogram.
Given a triangle, we may copy it
and paste to itself to make a
parallelogram,
h

b
Area
A triangle is half of a parallelogram.
Given a triangle, we may copy it
and paste to itself to make a
parallelogram,
h

b

h
b
Area
A triangle is half of a parallelogram.
Given a triangle, we may copy it
and paste to itself to make a
parallelogram, and the area of the
triangle is half of the area of the
parallelogram formed.
h

b

h
b
Area
A triangle is half of a parallelogram.
Given a triangle, we may copy it
and paste to itself to make a
parallelogram, and the area of the
triangle is half of the area of the
parallelogram formed.
Therefore the area of a triangle is
A = (b x h) ÷ 2 or A = b x h
2
where b = base and h = height.

h

b

h
b
Area
A triangle is half of a parallelogram.
Given a triangle, we may copy it
and paste to itself to make a
parallelogram, and the area of the
triangle is half of the area of the
parallelogram formed.
Therefore the area of a triangle is
A = (b x h) ÷ 2 or A = b x h
2
where b = base and h = height.
8 ft
12 ft

h

b

h
b
Area
A triangle is half of a parallelogram.
Given a triangle, we may copy it
and paste to itself to make a
parallelogram, and the area of the
triangle is half of the area of the
parallelogram formed.
Therefore the area of a triangle is
A = (b x h) ÷ 2 or A = b x h
2
where b = base and h = height.
8 ft

8 ft
12 ft

12 ft

h

b

h
b
Area
A triangle is half of a parallelogram.
Given a triangle, we may copy it
and paste to itself to make a
parallelogram, and the area of the
triangle is half of the area of the
parallelogram formed.
Therefore the area of a triangle is
A = (b x h) ÷ 2 or A = b x h
2
where b = base and h = height.
8 ft

8 ft

12 ft

12 ft

8 ft
12 ft

h

b

h
b
Area
A triangle is half of a parallelogram.
Given a triangle, we may copy it
and paste to itself to make a
parallelogram, and the area of the
triangle is half of the area of the
parallelogram formed.
Therefore the area of a triangle is
A = (b x h) ÷ 2 or A = b x h
2
where b = base and h = height.

h

b

h
b

8 ft

8 ft

12 ft

12 ft

8 ft

8 ft
12 ft

12 ft
Area
A triangle is half of a parallelogram.
Given a triangle, we may copy it
and paste to itself to make a
parallelogram, and the area of the
triangle is half of the area of the
parallelogram formed.
Therefore the area of a triangle is
A = (b x h) ÷ 2 or A = b x h
2
where b = base and h = height.
8 ft

8 ft

12 ft

12 ft

h

b

h
b

For example, the area of all
the triangles shown here is
(8 x 12) ÷ 2 = 48 ft2,
i.e. they are the same size.

8 ft

8 ft
12 ft

12 ft
Area
A trapezoid is a 4-sided figure with
one set of opposite sides parallel.
Area
A trapezoid is a 4-sided figure with
one set of opposite sides parallel. 5
Example B. Find the area of the
following trapezoid R.
Assume the unit is meter.

8
12
Area
8
A trapezoid is a 4-sided figure with
one set of opposite sides parallel. 5
12
Example B. Find the area of the
following trapezoid R.
Assume the unit is meter.
By cutting R parallel to one side as shown, we split R into two
areas, one parallelogram and one triangle.
Area
8
A trapezoid is a 4-sided figure with
one set of opposite sides parallel. 5
12
Example B. Find the area of the
following trapezoid R.
8
Assume the unit is meter.
By cutting R parallel to one side as shown, we split R into two
areas, one parallelogram and one triangle.
The parallelogram has base = 8 and height = 5,
Area
8
A trapezoid is a 4-sided figure with
one set of opposite sides parallel. 5
12
Example B. Find the area of the
following trapezoid R.
8
Assume the unit is meter.
By cutting R parallel to one side as shown, we split R into two
areas, one parallelogram and one triangle.
The parallelogram has base = 8 and height = 5,
hence its area is 8 x 5 = 40 m2.
Area
8
A trapezoid is a 4-sided figure with
one set of opposite sides parallel. 5
12
Example B. Find the area of the
following trapezoid R.
4
8
Assume the unit is meter.
By cutting R parallel to one side as shown, we split R into two
areas, one parallelogram and one triangle.
The parallelogram has base = 8 and height = 5,
hence its area is 8 x 5 = 40 m2.
The triangle has base = 4 and height = 5,
hence its area is (4 x 5) ÷ 2 = 10 m2.
Area
8
A trapezoid is a 4-sided figure with
one set of opposite sides parallel. 5
12
Example B. Find the area of the
following trapezoid R.
4
8
Assume the unit is meter.
By cutting R parallel to one side as shown, we split R into two
areas, one parallelogram and one triangle.
The parallelogram has base = 8 and height = 5,
hence its area is 8 x 5 = 40 m2.
The triangle has base = 4 and height = 5,
hence its area is (4 x 5) ÷ 2 = 10 m2.
Therefore the area of the trapezoid is 40 + 10 = 50 m2.
Area
8
A trapezoid is a 4-sided figure with
one set of opposite sides parallel. 5
12
Example B. Find the area of the
following trapezoid R.
4
8
Assume the unit is meter.
By cutting R parallel to one side as shown, we split R into two
areas, one parallelogram and one triangle.
The parallelogram has base = 8 and height = 5,
hence its area is 8 x 5 = 40 m2.
The triangle has base = 4 and height = 5,
hence its area is (4 x 5) ÷ 2 = 10 m2.
Therefore the area of the trapezoid is 40 + 10 = 50 m2.

We may find the area of any trapezoid by slicing it one
parallelogram and one triangle.
A direct formula for the area of a trapezoid may be obtained by
pasting two copies together as shown on the next slide.
Area
Suppose the lengths of the opposite
parallel sides a and b and the
height h of a trapezoid T are known.

a

T
h
b
Area

a

T

Suppose the lengths of the opposite
parallel sides a and b and the
height h of a trapezoid T are known.
By pasting another copy of the T
to itself, we obtain a parallelogram.

h
b

a
h
b
Area
Suppose the lengths of the opposite
parallel sides a and b and the
height h of a trapezoid T are known.
By pasting another copy of the T
to itself, we obtain a parallelogram.
The base of the parallelogram is
(a + b)

a

T
h
b

a

b

h
b

a
a+b
Area
Suppose the lengths of the opposite
parallel sides a and b and the
height h of a trapezoid T are known.
By pasting another copy of the T
to itself, we obtain a parallelogram.
The base of the parallelogram is
(a + b) so its area is (a + b)h.

a

T
h
b

a

b

h
b

a
a+b
Area
Suppose the lengths of the opposite
parallel sides a and b and the
height h of a trapezoid T are known.
By pasting another copy of the T
to itself, we obtain a parallelogram.
The base of the parallelogram is
(a + b) so its area is (a + b)h.
Therefore the area of a trapezoid T
is half of (a + b)h or that
T = (a + b)h ÷ 2

a

T
h
b

a

b

h
b

a
a+b
Area
Suppose the lengths of the opposite
parallel sides a and b and the
height h of a trapezoid T are known.
By pasting another copy of the T
to itself, we obtain a parallelogram.
The base of the parallelogram is
(a + b) so its area is (a + b)h.
Therefore the area of a trapezoid T
is half of (a + b)h or that
T = (a + b)h ÷ 2

a

T
h
b

a

b

h
b

a
a+b

For example, applying this formula in the last example,
we have the same answer:
8
5

12
Area
Suppose the lengths of the opposite
parallel sides a and b and the
height h of a trapezoid T are known.
By pasting another copy of the T
to itself, we obtain a parallelogram.
The base of the parallelogram is
(a + b) so its area is (a + b)h.
Therefore the area of a trapezoid T
is half of (a + b)h or that
T = (a + b)h ÷ 2

a

T
h
b

a

b

h
b

a
a+b

For example, applying this formula in the last example,
we have the same answer:
8
(12 + 8) 5÷2 = 100÷2 = 50.
5

12

More Related Content

PPT
Area & volume
PPTX
CLASS IX MATHS PPT
DOCX
Gre solid 02 math geo
PDF
How to Calculate Distances from Centerline to Inside Walls of Domes, for Any ...
DOCX
Measurement of Three Dimensional Figures _Module and test questions.
ODP
Questions of mensuration, area and volume for aptitude tests
PPT
Present(Pbwik)I
DOCX
Assessment forfolio questions
Area & volume
CLASS IX MATHS PPT
Gre solid 02 math geo
How to Calculate Distances from Centerline to Inside Walls of Domes, for Any ...
Measurement of Three Dimensional Figures _Module and test questions.
Questions of mensuration, area and volume for aptitude tests
Present(Pbwik)I
Assessment forfolio questions

What's hot (20)

PDF
Module 7 geometry of shape and size
PDF
SURFACE AREAS AND VOLUMES OF SOLID FIGURES - MENSURATION
PDF
Module 8 geometry of shape and size
PDF
Module 6 geometry of shape and size
PDF
Area solv
PPT
Present(Eng)
PPTX
Mensuration (1)
PPTX
53 pythagorean theorem and square roots
PPT
Geometry unit 11.1
PPSX
Surface area and volume ssolids
PPT
Volume- Mathematics
PPT
Finding Area
PPT
9 perimeter, area volume
PPTX
Mathematics – Sphere and Prism
PPTX
Math 103-Mensuration-Areas-sem-dfs
PPTX
MATHS PROJECT
PPT
Surface Area and Volume
PPTX
Surface area and volume for 9th class maths
PPTX
Perimeter, area and volume - Definitions and Formulas
Module 7 geometry of shape and size
SURFACE AREAS AND VOLUMES OF SOLID FIGURES - MENSURATION
Module 8 geometry of shape and size
Module 6 geometry of shape and size
Area solv
Present(Eng)
Mensuration (1)
53 pythagorean theorem and square roots
Geometry unit 11.1
Surface area and volume ssolids
Volume- Mathematics
Finding Area
9 perimeter, area volume
Mathematics – Sphere and Prism
Math 103-Mensuration-Areas-sem-dfs
MATHS PROJECT
Surface Area and Volume
Surface area and volume for 9th class maths
Perimeter, area and volume - Definitions and Formulas
Ad

Similar to 1.12 area w (20)

PPTX
Area and Perimeter of Rectangles Education Presentation in Pink Blue Cream No...
PDF
Mathematics: Perimeter and Area Lesson
PDF
Perimeter and Area of Polygons
PPTX
Presentación de medicina Salud mental Ilustrativo Turquesa Beige (3).pptx
PPTX
Areas, shapes and perimeters
PPTX
Class 5th(maths) how many squares ppt
PPT
Area 110906060641-phpapp01
PDF
Geometry: Perimeter and Area
PPTX
Chapter 11 Perimeter and Area for grade 7.pptx
PPT
Area of-rectangles
PPT
Length and area
PPT
E2209310017_Mathematics_B.Ed II Year.ppt
PPTX
4 Geometry Area and Perimeter
PPTX
Area and Perimeter of Rectangles
PPTX
Perimeter and area 1
PPTX
GRADE 4 MATH AREA and PERIMETER of RECTANGLES.pptx
PPT
Area and perimeter
PPT
Area and perimeter
PPTX
Area of Polygons_Composite Figures_.pptx
PPTX
Area of Plane Figures
Area and Perimeter of Rectangles Education Presentation in Pink Blue Cream No...
Mathematics: Perimeter and Area Lesson
Perimeter and Area of Polygons
Presentación de medicina Salud mental Ilustrativo Turquesa Beige (3).pptx
Areas, shapes and perimeters
Class 5th(maths) how many squares ppt
Area 110906060641-phpapp01
Geometry: Perimeter and Area
Chapter 11 Perimeter and Area for grade 7.pptx
Area of-rectangles
Length and area
E2209310017_Mathematics_B.Ed II Year.ppt
4 Geometry Area and Perimeter
Area and Perimeter of Rectangles
Perimeter and area 1
GRADE 4 MATH AREA and PERIMETER of RECTANGLES.pptx
Area and perimeter
Area and perimeter
Area of Polygons_Composite Figures_.pptx
Area of Plane Figures
Ad

More from Tzenma (20)

PPTX
6 slopes and difference quotient x
PPTX
5 algebra of functions
PPTX
4 graphs of equations conic sections-circles
PPTX
3 graphs of second degree functions x
PPTX
2 graphs of first degree functions x
PPTX
1 functions
PPTX
9 rational equations word problems-x
PPTX
9 rational equations word problems-x
PPTX
7 proportions x
PPTX
10 complex fractions x
PPTX
6 addition and subtraction ii x
PPTX
5 addition and subtraction i x
PPTX
4 the lcm and clearing denominators x
PPTX
3 multiplication and division of rational expressions x
PPTX
2 cancellation x
PPTX
1 rational expressions x
PPTX
8 linear word problems in x&y x
PPTX
7 system of linear equations ii x
PPTX
6 system of linear equations i x
PPTX
5 equations of lines x
6 slopes and difference quotient x
5 algebra of functions
4 graphs of equations conic sections-circles
3 graphs of second degree functions x
2 graphs of first degree functions x
1 functions
9 rational equations word problems-x
9 rational equations word problems-x
7 proportions x
10 complex fractions x
6 addition and subtraction ii x
5 addition and subtraction i x
4 the lcm and clearing denominators x
3 multiplication and division of rational expressions x
2 cancellation x
1 rational expressions x
8 linear word problems in x&y x
7 system of linear equations ii x
6 system of linear equations i x
5 equations of lines x

Recently uploaded (20)

PDF
African Communication Research: A review
PDF
faiz-khans about Radiotherapy Physics-02.pdf
PPTX
pharmaceutics-1unit-1-221214121936-550b56aa.pptx
PPTX
BSCE 2 NIGHT (CHAPTER 2) just cases.pptx
PDF
Hospital Case Study .architecture design
PDF
MICROENCAPSULATION_NDDS_BPHARMACY__SEM VII_PCI Syllabus.pdf
PDF
PUBH1000 - Module 6: Global Health Tute Slides
PDF
Journal of Dental Science - UDMY (2022).pdf
PDF
Health aspects of bilberry: A review on its general benefits
PPTX
PLASMA AND ITS CONSTITUENTS 123.pptx
PPTX
Thinking Routines and Learning Engagements.pptx
PDF
1.Salivary gland disease.pdf 3.Bleeding and Clotting Disorders.pdf important
PDF
anganwadi services for the b.sc nursing and GNM
PDF
Disorder of Endocrine system (1).pdfyyhyyyy
PPTX
Macbeth play - analysis .pptx english lit
PDF
0520_Scheme_of_Work_(for_examination_from_2021).pdf
PDF
Myanmar Dental Journal, The Journal of the Myanmar Dental Association (2015).pdf
PPTX
UNIT_2-__LIPIDS[1].pptx.................
PDF
M.Tech in Aerospace Engineering | BIT Mesra
PDF
Horaris_Grups_25-26_Definitiu_15_07_25.pdf
African Communication Research: A review
faiz-khans about Radiotherapy Physics-02.pdf
pharmaceutics-1unit-1-221214121936-550b56aa.pptx
BSCE 2 NIGHT (CHAPTER 2) just cases.pptx
Hospital Case Study .architecture design
MICROENCAPSULATION_NDDS_BPHARMACY__SEM VII_PCI Syllabus.pdf
PUBH1000 - Module 6: Global Health Tute Slides
Journal of Dental Science - UDMY (2022).pdf
Health aspects of bilberry: A review on its general benefits
PLASMA AND ITS CONSTITUENTS 123.pptx
Thinking Routines and Learning Engagements.pptx
1.Salivary gland disease.pdf 3.Bleeding and Clotting Disorders.pdf important
anganwadi services for the b.sc nursing and GNM
Disorder of Endocrine system (1).pdfyyhyyyy
Macbeth play - analysis .pptx english lit
0520_Scheme_of_Work_(for_examination_from_2021).pdf
Myanmar Dental Journal, The Journal of the Myanmar Dental Association (2015).pdf
UNIT_2-__LIPIDS[1].pptx.................
M.Tech in Aerospace Engineering | BIT Mesra
Horaris_Grups_25-26_Definitiu_15_07_25.pdf

1.12 area w

  • 2. Area If we connect the two ends of a rope that’s resting flat in a plane, we obtain a loop.
  • 3. Area If we connect the two ends of a rope that’s resting flat in a plane, we obtain a loop. The loop forms a perimeter or border that encloses an area, i.e. a surface in the plane.
  • 4. Area If we connect the two ends of a rope that’s resting flat in a plane, we obtain a loop. The loop forms a perimeter or border that encloses an area, i.e. a surface in the plane. The word “area” also denotes the amount of surface enclosed which is defined below.
  • 5. Area If we connect the two ends of a rope that’s resting flat in a plane, we obtain a loop. The loop forms a perimeter or border that encloses an area, i.e. a surface in the plane. The word “area” also denotes the amount of surface enclosed which is defined below. 1 in 1 in 1m 1m 1 mi 1 mi
  • 6. Area If we connect the two ends of a rope that’s resting flat in a plane, we obtain a loop. The loop forms a perimeter or border that encloses an area, i.e. a surface in the plane. The word “area” also denotes the amount of surface enclosed which is defined below. If each side of a square is 1 unit, then we define the area of the square to be 1 unit x 1 unit = 1 unit2, i.e. 1 square-unit. 1 in 1 in 1m 1m 1 mi 1 mi
  • 7. Area If we connect the two ends of a rope that’s resting flat in a plane, we obtain a loop. The loop forms a perimeter or border that encloses an area, i.e. a surface in the plane. The word “area” also denotes the amount of surface enclosed which is defined below. If each side of a square is 1 unit, then we define the area of the square to be 1 unit x 1 unit = 1 unit2, i.e. 1 square-unit. Hence the areas of the following squares are: 1 in 1m 1 mi 1 in 1m 1 mi
  • 8. Area If we connect the two ends of a rope that’s resting flat in a plane, we obtain a loop. The loop forms a perimeter or border that encloses an area, i.e. a surface in the plane. The word “area” also denotes the amount of surface enclosed which is defined below. If each side of a square is 1 unit, then we define the area of the square to be 1 unit x 1 unit = 1 unit2, i.e. 1 square-unit. Hence the areas of the following squares are: 1 in 1m 1 mi 1 in 1 in2 1 square-inch 1m 1 mi
  • 9. Area If we connect the two ends of a rope that’s resting flat in a plane, we obtain a loop. The loop forms a perimeter or border that encloses an area, i.e. a surface in the plane. The word “area” also denotes the amount of surface enclosed which is defined below. If each side of a square is 1 unit, then we define the area of the square to be 1 unit x 1 unit = 1 unit2, i.e. 1 square-unit. Hence the areas of the following squares are: 1 in 1m 1 mi 1 in 1 in2 1 square-inch 1m 1 m2 1 square-meter 1 mi 1 mi2 1 square-mile
  • 10. Area A 2 mi x 3 mi rectangle may be cut into six 1 x 1 squares so it covers an area of 2 x 3 = 6 mi2 (square miles). 3 mi 2 mi
  • 11. Area A 2 mi x 3 mi rectangle may be cut into six 1 x 1 squares so it covers an area of 2 x 3 = 6 mi2 (square miles). 3 mi 2 mi 2x3 = 6 mi2
  • 12. Area A 2 mi x 3 mi rectangle may be cut into 2 mi six 1 x 1 squares so it covers an area of 2 x 3 = 6 mi2 (square miles). In general, given the rectangle with height = h (units) width* = w (units), h 2). then its area A = h x w (unit * For our discussion, the “width” is the horizontal length. 3 mi 2x3 = 6 mi2 w
  • 13. Area 3 mi A 2 mi x 3 mi rectangle may be cut into 2x3 2 mi six 1 x 1 squares so it covers an area of = 6 mi2 2 x 3 = 6 mi2 (square miles). In general, given the rectangle with w height = h (units) width* = w (units), h A = h x w (unit2) then its area A = h x w (unit2). * For our discussion, the “width” is the horizontal length.
  • 14. Area 3 mi A 2 mi x 3 mi rectangle may be cut into 2x3 2 mi six 1 x 1 squares so it covers an area of = 6 mi2 2 x 3 = 6 mi2 (square miles). In general, given the rectangle with w height = h (units) width* = w (units), h A = h x w (unit2) then its area A = h x w (unit2). A square is a rectangle with four equal sides s as shown. s s A square * For our discussion, the “width” is the horizontal length.
  • 15. Area 3 mi A 2 mi x 3 mi rectangle may be cut into 2x3 2 mi six 1 x 1 squares so it covers an area of = 6 mi2 2 x 3 = 6 mi2 (square miles). In general, given the rectangle with w height = h (units) width* = w (units), h A = h x w (unit2) then its area A = h x w (unit2). A square is a rectangle with four equal sides s as shown. s The perimeter of a square is s + s + s + s = 4s. The area of a square is s*s = s2. s A square * For our discussion, the “width” is the horizontal length.
  • 16. Area 3 mi A 2 mi x 3 mi rectangle may be cut into 2x3 2 mi six 1 x 1 squares so it covers an area of = 6 mi2 2 x 3 = 6 mi2 (square miles). In general, given the rectangle with w height = h (units) width* = w (units), h A = h x w (unit2) then its area A = h x w (unit2). A square is a rectangle with four equal sides s as shown. s The perimeter of a square is s + s + s + s = 4s. The area of a square is s*s = s2. s So the perimeter of a 10 m x 10 m square is 40 m. A square 2 = 100 m2. and its area is 10 * For our discussion, the “width” is the horizontal length.
  • 17. Area 3 mi A 2 mi x 3 mi rectangle may be cut into 2x3 2 mi six 1 x 1 squares so it covers an area of = 6 mi2 2 x 3 = 6 mi2 (square miles). In general, given the rectangle with w height = h (units) width* = w (units), h A = h x w (unit2) then its area A = h x w (unit2). A square is a rectangle with four equal sides s as shown. s The perimeter of a square is s + s + s + s = 4s. The area of a square is s*s = s2. s So the perimeter of a 10 m x 10 m square is 40 m. A square 2 = 100 m2. and its area is 10 s An area with four equal sides in general is called a rhombus (diamond shapes). s A rhombus * For our discussion, the “width” is the horizontal length.
  • 18. Area 3 mi A 2 mi x 3 mi rectangle may be cut into 2x3 2 mi six 1 x 1 squares so it covers an area of = 6 mi2 2 x 3 = 6 mi2 (square miles). In general, given the rectangle with w height = h (units) width* = w (units), h A = h x w (unit2) then its area A = h x w (unit2). A square is a rectangle with four equal sides s as shown. s The perimeter of a square is s + s + s + s = 4s. The area of a square is s*s = s2. s So the perimeter of a 10 m x 10 m square is 40 m. A square 2 = 100 m2. and its area is 10 s An area with four equal sides in general is called a rhombus (diamond shapes). The perimeter of s a rhombus is 4s, but its area depends on its shape. A rhombus * For our discussion, the “width” is the horizontal length.
  • 19. Area Example A. Find the area of the following shape R. Assume the unit is meter. 4 4 R 12 12
  • 20. Area Example A. Find the area of the following shape R. Assume the unit is meter. 4 4 R 12 12
  • 21. Area Example A. Find the area of the following shape R. Assume the unit is meter. There are two basic approaches. 4 4 R 12 12
  • 22. Area Example A. Find the area of the following shape R. Assume the unit is meter. There are two basic approaches. I. We may view R as a 12 x 12 = 144 m2 square with a 4 x 8 = 32 m2 corner removed. 8 4 R 12 12 4 4 4 R 12 12
  • 23. Area Example A. Find the area of the following shape R. Assume the unit is meter. There are two basic approaches. I. We may view R as a 12 x 12 = 144 m2 square with a 4 x 8 = 32 m2 corner removed. Hence the area of R is 144 – 32 = 112 m2 8 4 R 12 12 4 4 4 R 12 12
  • 24. Area Example A. Find the area of the following shape R. Assume the unit is meter. 4 R There are two basic approaches. 12 12 I. We may view R as a 12 x 12 = 144 m2 square Il. We may dissect R into two 2 with a 4 x 8 = 32 m rectangles I and II as shown. corner removed. Hence the area of R is 144 – 32 = 112 m2 8 8 4 R 12 4 4 I 12 12 4 II 12 4
  • 25. Area Example A. Find the area of the following shape R. Assume the unit is meter. 4 R There are two basic approaches. 12 12 I. We may view R as a 12 x 12 = 144 m2 square Il. We may dissect R into two 2 with a 4 x 8 = 32 m rectangles I and II as shown. corner removed. Area of I is 12 x 8 = 96, Hence the area of R is area of II is 4 x 4 = 16. 144 – 32 = 112 m2 8 8 4 R 12 4 4 I 12 12 4 II 12 4
  • 26. Area Example A. Find the area of the following shape R. Assume the unit is meter. 4 R 4 There are two basic approaches. 12 12 I. We may view R as a 12 x 12 = 144 m2 square Il. We may dissect R into two 2 with a 4 x 8 = 32 m rectangles I and II as shown. corner removed. Area of I is 12 x 8 = 96, Hence the area of R is area of II is 4 x 4 = 16. 144 – 32 The area of R is the sum of the = 112 m2 two or 96 + 16 = 112 m2. 8 8 4 R 12 4 4 I 12 12 4 II 12
  • 27. Area Example A. Find the area of the following shape R. Assume the unit is meter. 4 4 R There are two basic approaches. 12 12 I. We may view R as a 12 x 12 = 144 m2 square Il. We may dissect R into two 2 with a 4 x 8 = 32 m rectangles I and II as shown. corner removed. Area of I is 12 x 8 = 96, Hence the area of R is area of II is 4 x 4 = 16. 144 – 32 The area of R is the sum of the = 112 m2 two or 96 + 16 = 112 m2. 8 4 R 12 4 4 I 12 12 8 8 iii 4 II 12 12 4 4 iv (We may also cut R into iii and iv as shown here.) 12
  • 28. Area b. Find the area of the following shape R. Let’s cut R into three rectangles as shown. 2 ft
  • 29. Area b. Find the area of the following shape R. Let’s cut R into three rectangles as shown. I II III 2 ft
  • 30. Area b. Find the area of the following shape R. Let’s cut R into three rectangles as shown. Area of I is 2 x 2 = 4, I II III 2 ft
  • 31. Area b. Find the area of the following shape R. Let’s cut R into three rectangles as shown. Area of I is 2 x 2 = 4, area of II is 2 x 6 = 12, I II III 2 ft
  • 32. Area b. Find the area of the following shape R. Let’s cut R into three rectangles as shown. Area of I is 2 x 2 = 4, area of II is 2 x 6 = 12, and area of III is 2 x 5 = 10. I II III 2 ft
  • 33. Area b. Find the area of the following shape R. Let’s cut R into three rectangles as shown. Area of I is 2 x 2 = 4, area of II is 2 x 6 = 12, and area of III is 2 x 5 = 10. Hence the total area is 4 + 12 + 10 = 16 ft2. I II III 2 ft
  • 34. Area b. Find the area of the following shape R. Let’s cut R into three rectangles as shown. Area of I is 2 x 2 = 4, area of II is 2 x 6 = 12, and area of III is 2 x 5 = 10. Hence the total area is 4 + 12 + 10 = 16 ft2. c. Two rectangular walk-ways crosses each other perpendicularly as shown. The larger one is 25 ft x 6 ft and the smaller one is 20 ft x 4 ft. What is the total area they cover? I 2 ft II III 20 ft 4 ft 25 ft 6 ft
  • 35. Area b. Find the area of the following shape R. Let’s cut R into three rectangles as shown. Area of I is 2 x 2 = 4, area of II is 2 x 6 = 12, and area of III is 2 x 5 = 10. Hence the total area is 4 + 12 + 10 = 16 ft2. c. Two rectangular walk-ways crosses each other perpendicularly as shown. The larger one is 25 ft x 6 ft and the smaller one is 20 ft x 4 ft. What is the total area they cover? The area of the larger strip is 25 x 6 = 150 ft2 I 2 ft II III 20 ft 4 ft 25 ft 6 ft
  • 36. Area b. Find the area of the following shape R. Let’s cut R into three rectangles as shown. Area of I is 2 x 2 = 4, area of II is 2 x 6 = 12, and area of III is 2 x 5 = 10. Hence the total area is 4 + 12 + 10 = 16 ft2. I 2 ft II III 20 ft c. Two rectangular walk-ways crosses each other perpendicularly as shown. The larger one is 25 ft x 6 ft and the smaller one is 20 ft x 4 ft. What is the total area they cover? 25 ft 2 The area of the larger strip is 25 x 6 = 150 ft and the area of the smaller strip is 20 x 4 = 80 ft2. 4 ft 6 ft
  • 37. Area b. Find the area of the following shape R. Let’s cut R into three rectangles as shown. Area of I is 2 x 2 = 4, area of II is 2 x 6 = 12, and area of III is 2 x 5 = 10. Hence the total area is 4 + 12 + 10 = 16 ft2. I 2 ft II III 20 ft c. Two rectangular walk-ways crosses each other perpendicularly as shown. The larger one is 25 ft x 6 ft and the smaller one is 20 ft x 4 ft. What is the total area they cover? 25 ft 2 The area of the larger strip is 25 x 6 = 150 ft and the area of the smaller strip is 20 x 4 = 80 ft2. Their sum 150 + 80 = 230 includes the 4 ft x 6 ft (= 24 ft2) rectangular overlap twice. 4 ft 6 ft
  • 38. Area b. Find the area of the following shape R. Let’s cut R into three rectangles as shown. Area of I is 2 x 2 = 4, area of II is 2 x 6 = 12, and area of III is 2 x 5 = 10. Hence the total area is 4 + 12 + 10 = 16 ft2. I 2 ft II III 20 ft c. Two rectangular walk-ways crosses each other perpendicularly as shown. The larger one is 25 ft x 6 ft and the smaller one is 20 ft x 4 ft. What is the total area they cover? 25 ft 2 The area of the larger strip is 25 x 6 = 150 ft and the area of the smaller strip is 20 x 4 = 80 ft2. Their sum 150 + 80 = 230 includes the 4 ft x 6 ft (= 24 ft2) rectangular overlap twice. Hence the total area covered is 230 – 24 = 206 ft2. 4 ft 6 ft
  • 39. Area A parallelogram is a shape enclosed by two sets of parallel lines. h b
  • 40. Area A parallelogram is a shape enclosed by two sets of parallel lines. By cutting and pasting, we may arrange a parallelogram into a rectangle. h b
  • 41. Area A parallelogram is a shape enclosed by two sets of parallel lines. By cutting and pasting, we may arrange a parallelogram into a rectangle. h b
  • 42. Area A parallelogram is a shape enclosed by two sets of parallel lines. By cutting and pasting, we may arrange a parallelogram into a rectangle. h h b b
  • 43. Area A parallelogram is a shape enclosed by two sets of parallel lines. By cutting and pasting, we may arrange a parallelogram into a rectangle. h h b b Hence the area of the parallelogram is A = b x h where b = base and h = height.
  • 44. Area A parallelogram is a shape enclosed by two sets of parallel lines. By cutting and pasting, we may arrange a parallelogram into a rectangle. h h b b Hence the area of the parallelogram is A = b x h where b = base and h = height. 8 ft 12 ft
  • 45. Area A parallelogram is a shape enclosed by two sets of parallel lines. By cutting and pasting, we may arrange a parallelogram into a rectangle. h h b b Hence the area of the parallelogram is A = b x h where b = base and h = height. 8 ft 12 ft 8 ft 12 ft
  • 46. Area A parallelogram is a shape enclosed by two sets of parallel lines. By cutting and pasting, we may arrange a parallelogram into a rectangle. h h b b Hence the area of the parallelogram is A = b x h where b = base and h = height. 8 ft 12 ft 8 ft 8 ft 12 ft 12 ft
  • 47. Area A parallelogram is a shape enclosed by two sets of parallel lines. By cutting and pasting, we may arrange a parallelogram into a rectangle. h h b b Hence the area of the parallelogram is A = b x h where b = base and h = height. 8 ft 12 ft 8 ft 8 ft 12 ft 12 ft 8 ft 12 ft
  • 48. Area A parallelogram is a shape enclosed by two sets of parallel lines. By cutting and pasting, we may arrange a parallelogram into a rectangle. h h b b Hence the area of the parallelogram is A = b x h where b = base and h = height. For example, the area of all the parallelograms shown 8 ft 8 ft 12 ft here is 8 x 12 = 96 ft2, 12 ft so they are the same size. 8 ft 12 ft 8 ft 12 ft
  • 49. Area A triangle is half of a parallelogram.
  • 50. Area A triangle is half of a parallelogram. Given a triangle, we may copy it and paste to itself to make a parallelogram, h b
  • 51. Area A triangle is half of a parallelogram. Given a triangle, we may copy it and paste to itself to make a parallelogram, h b h b
  • 52. Area A triangle is half of a parallelogram. Given a triangle, we may copy it and paste to itself to make a parallelogram, and the area of the triangle is half of the area of the parallelogram formed. h b h b
  • 53. Area A triangle is half of a parallelogram. Given a triangle, we may copy it and paste to itself to make a parallelogram, and the area of the triangle is half of the area of the parallelogram formed. Therefore the area of a triangle is A = (b x h) ÷ 2 or A = b x h 2 where b = base and h = height. h b h b
  • 54. Area A triangle is half of a parallelogram. Given a triangle, we may copy it and paste to itself to make a parallelogram, and the area of the triangle is half of the area of the parallelogram formed. Therefore the area of a triangle is A = (b x h) ÷ 2 or A = b x h 2 where b = base and h = height. 8 ft 12 ft h b h b
  • 55. Area A triangle is half of a parallelogram. Given a triangle, we may copy it and paste to itself to make a parallelogram, and the area of the triangle is half of the area of the parallelogram formed. Therefore the area of a triangle is A = (b x h) ÷ 2 or A = b x h 2 where b = base and h = height. 8 ft 8 ft 12 ft 12 ft h b h b
  • 56. Area A triangle is half of a parallelogram. Given a triangle, we may copy it and paste to itself to make a parallelogram, and the area of the triangle is half of the area of the parallelogram formed. Therefore the area of a triangle is A = (b x h) ÷ 2 or A = b x h 2 where b = base and h = height. 8 ft 8 ft 12 ft 12 ft 8 ft 12 ft h b h b
  • 57. Area A triangle is half of a parallelogram. Given a triangle, we may copy it and paste to itself to make a parallelogram, and the area of the triangle is half of the area of the parallelogram formed. Therefore the area of a triangle is A = (b x h) ÷ 2 or A = b x h 2 where b = base and h = height. h b h b 8 ft 8 ft 12 ft 12 ft 8 ft 8 ft 12 ft 12 ft
  • 58. Area A triangle is half of a parallelogram. Given a triangle, we may copy it and paste to itself to make a parallelogram, and the area of the triangle is half of the area of the parallelogram formed. Therefore the area of a triangle is A = (b x h) ÷ 2 or A = b x h 2 where b = base and h = height. 8 ft 8 ft 12 ft 12 ft h b h b For example, the area of all the triangles shown here is (8 x 12) ÷ 2 = 48 ft2, i.e. they are the same size. 8 ft 8 ft 12 ft 12 ft
  • 59. Area A trapezoid is a 4-sided figure with one set of opposite sides parallel.
  • 60. Area A trapezoid is a 4-sided figure with one set of opposite sides parallel. 5 Example B. Find the area of the following trapezoid R. Assume the unit is meter. 8 12
  • 61. Area 8 A trapezoid is a 4-sided figure with one set of opposite sides parallel. 5 12 Example B. Find the area of the following trapezoid R. Assume the unit is meter. By cutting R parallel to one side as shown, we split R into two areas, one parallelogram and one triangle.
  • 62. Area 8 A trapezoid is a 4-sided figure with one set of opposite sides parallel. 5 12 Example B. Find the area of the following trapezoid R. 8 Assume the unit is meter. By cutting R parallel to one side as shown, we split R into two areas, one parallelogram and one triangle. The parallelogram has base = 8 and height = 5,
  • 63. Area 8 A trapezoid is a 4-sided figure with one set of opposite sides parallel. 5 12 Example B. Find the area of the following trapezoid R. 8 Assume the unit is meter. By cutting R parallel to one side as shown, we split R into two areas, one parallelogram and one triangle. The parallelogram has base = 8 and height = 5, hence its area is 8 x 5 = 40 m2.
  • 64. Area 8 A trapezoid is a 4-sided figure with one set of opposite sides parallel. 5 12 Example B. Find the area of the following trapezoid R. 4 8 Assume the unit is meter. By cutting R parallel to one side as shown, we split R into two areas, one parallelogram and one triangle. The parallelogram has base = 8 and height = 5, hence its area is 8 x 5 = 40 m2. The triangle has base = 4 and height = 5, hence its area is (4 x 5) ÷ 2 = 10 m2.
  • 65. Area 8 A trapezoid is a 4-sided figure with one set of opposite sides parallel. 5 12 Example B. Find the area of the following trapezoid R. 4 8 Assume the unit is meter. By cutting R parallel to one side as shown, we split R into two areas, one parallelogram and one triangle. The parallelogram has base = 8 and height = 5, hence its area is 8 x 5 = 40 m2. The triangle has base = 4 and height = 5, hence its area is (4 x 5) ÷ 2 = 10 m2. Therefore the area of the trapezoid is 40 + 10 = 50 m2.
  • 66. Area 8 A trapezoid is a 4-sided figure with one set of opposite sides parallel. 5 12 Example B. Find the area of the following trapezoid R. 4 8 Assume the unit is meter. By cutting R parallel to one side as shown, we split R into two areas, one parallelogram and one triangle. The parallelogram has base = 8 and height = 5, hence its area is 8 x 5 = 40 m2. The triangle has base = 4 and height = 5, hence its area is (4 x 5) ÷ 2 = 10 m2. Therefore the area of the trapezoid is 40 + 10 = 50 m2. We may find the area of any trapezoid by slicing it one parallelogram and one triangle. A direct formula for the area of a trapezoid may be obtained by pasting two copies together as shown on the next slide.
  • 67. Area Suppose the lengths of the opposite parallel sides a and b and the height h of a trapezoid T are known. a T h b
  • 68. Area a T Suppose the lengths of the opposite parallel sides a and b and the height h of a trapezoid T are known. By pasting another copy of the T to itself, we obtain a parallelogram. h b a h b
  • 69. Area Suppose the lengths of the opposite parallel sides a and b and the height h of a trapezoid T are known. By pasting another copy of the T to itself, we obtain a parallelogram. The base of the parallelogram is (a + b) a T h b a b h b a a+b
  • 70. Area Suppose the lengths of the opposite parallel sides a and b and the height h of a trapezoid T are known. By pasting another copy of the T to itself, we obtain a parallelogram. The base of the parallelogram is (a + b) so its area is (a + b)h. a T h b a b h b a a+b
  • 71. Area Suppose the lengths of the opposite parallel sides a and b and the height h of a trapezoid T are known. By pasting another copy of the T to itself, we obtain a parallelogram. The base of the parallelogram is (a + b) so its area is (a + b)h. Therefore the area of a trapezoid T is half of (a + b)h or that T = (a + b)h ÷ 2 a T h b a b h b a a+b
  • 72. Area Suppose the lengths of the opposite parallel sides a and b and the height h of a trapezoid T are known. By pasting another copy of the T to itself, we obtain a parallelogram. The base of the parallelogram is (a + b) so its area is (a + b)h. Therefore the area of a trapezoid T is half of (a + b)h or that T = (a + b)h ÷ 2 a T h b a b h b a a+b For example, applying this formula in the last example, we have the same answer: 8 5 12
  • 73. Area Suppose the lengths of the opposite parallel sides a and b and the height h of a trapezoid T are known. By pasting another copy of the T to itself, we obtain a parallelogram. The base of the parallelogram is (a + b) so its area is (a + b)h. Therefore the area of a trapezoid T is half of (a + b)h or that T = (a + b)h ÷ 2 a T h b a b h b a a+b For example, applying this formula in the last example, we have the same answer: 8 (12 + 8) 5÷2 = 100÷2 = 50. 5 12