SQUARE ROOTS AND
IRRATIONAL NUMBERS
SQUARE ROOTS AND
IRRATIONAL NUMBERS
SQUARE ROOTS AND
IRRATIONAL NUMBERS
SQUARE ROOTS AND
IRRATIONAL NUMBERS
SQUARES AND ROOTS
2
2
2
2
2
2
2
2
2
2
2
2
1 1
2 4
3 9
4 16
5 25
6 36
7 49
8 64
9 81
10 100
11 121
12 144












1 1
4 2
9 3
16 4
25 5
36 6
49 7
64 8
81 9
100 10
121 11
144 12












SQUARES AND ROOTS
2
2
2
2
2
2
2
2
2
2
2
2
1 1
2 4
3 9
4 16
5 25
6 36
7 49
8 64
9 81
10 100
11 121
12 144












1 1
4 2
9 3
16 4
25 5
36 6
49 7
64 8
81 9
100 10
121 11
144 12












SQUARES AND ROOTS
2
2
2
2
2
2
2
2
2
2
2
2
1 1
2 4
3 9
4 16
5 25
6 36
7 49
8 64
9 81
10 100
11 121
12 144












1 1
4 2
9 3
16 4
25 5
36 6
49 7
64 8
81 9
100 10
121 11
144 12












NOTE!!!
Notice that squares and square roots are inverses (opposites) of each
other.
NOTE!!!
Notice that squares and square roots are inverses (opposites) of each
other.
NOTE!!!
Notice that squares and square roots are inverses (opposites) of each
other.
NOTE!!!
Notice that squares and square roots are inverses (opposites) of each
other.
NOTE!!!
Notice that squares and square roots are inverses (opposites) of each
other.
NOTE!!!
Notice that squares and square roots are inverses (opposites) of each
other.
NOTE!!!
Notice that squares and square roots are inverses (opposites) of each
other.
ESTIMATING SQUARE ROOTS
Once you memorized squares and their roots, we can estimate square
roots that are not perfect squares
For example, what about
8
ESTIMATING SQUARE ROOTS
We find the two perfect squares that are before and after the
square root of 8. . .
and
Look at them on a number line:
4 5
9
4
9
6 7 8
3
2
2 3
ESTIMATING SQUARE ROOTS
We can see that is between 2 and 3 but
is closer to 3. We would say that is approximately
3.
4 5 9
6 7 8
3
2
2 3
8
8
TRY THIS:
ESTIMATE TO THE NEAREST WHOLE NUMBER
27
78

50
Click to the next slide to see if you are right!
TRY THIS:
ESTIMATE TO THE NEAREST WHOLE NUMBER
27
78

50
5
-9
7
Rational number- can be written as a fraction
Irrational number- cannot be written as a fraction because:
 it is a non-terminating decimal
 it is a decimal that does NOT repeat
* The square roots of ALL perfect squares are rational.
* The square roots of numbers that are NOT perfect squares
are irrational.
TRY THIS: IDENTIFY EACH NUMBER AS
RATIONAL OR IRRATIONAL
2
81

0.53
0.627
13.875931...
IDENTIFY EACH NUMBER AS RATIONAL
OR IRRATIONAL.
2
81

0.53
0.627
13.875931...
Irrational
Rational
Rational
Rational
Irrational
IDENTIFY EACH NUMBER AS RATIONAL
OR IRRATIONAL.
2
81

0.53
0.627
13.875931...
Irrational
Rational
Rational
Rational
Irrational
IDENTIFY EACH NUMBER AS RATIONAL
OR IRRATIONAL.
2
81

0.53
0.627
13.875931...
Irrational
Rational
Rational
Rational
Irrational
IDENTIFY EACH NUMBER AS RATIONAL
OR IRRATIONAL.
2
81

0.53
0.627
13.875931...
Irrational
Rational
Rational
Rational
Irrational

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