1.2 Points Lines and Planes Powerpoint.ppt
- 1. 1.2 Points, Lines, and Planes
- 2. What is a definition? Known words used to describe a new word Undefined terms – are terms not formally defined. There are three undefined terms in geometry: 1. Point 2. Line 3. Plane
- 3. Point 1. A location in space. 2. Has no dimension (no length, no width, no depth). 3. Usually represented by a dot. 4. Named using one capital letter.
- 5. Line 1. A series of points that extends in opposite directions without end. 2. One-dimensional (length). 3. Has an arrowhead on each end representing the fact that it goes on forever. 4. Always straight. 5. Named with a lowercase script letter or by 2 points on the line
- 6. Line A B l Can be called: Line l Line AB or AB Line BA or BA For example:
- 7. Plane 1. A flat surface that extends forever in two dimensions (length & width). 2. Contains infinitely many points and lines. 3. Usually represented by a four-sided figure. 4. Named with a capital script letter or 3 points on the surface of the plane
- 8. Plane A B C W Can be named: Plane W Plane ABC, plane BCA, plane CBA, etc. For example:
- 9. More Definitions Collinear points – points that can lie on the same line.
- 10. More Definitions Noncollinear points – D
- 11. More Definitions Coplanar points – points that can lie on the same plane.
- 12. More Definitions Noncoplanar points – D A
- 13. More Definitions Equidistant – equally distant
- 14. More Definitions Intersect – Two or more figures intersect if they have one or more points in common. Intersection – All points or sets of points the figures have in common.
- 15. When a line and a point intersect, their intersection is a point. B l
- 16. When 2 lines intersect, their intersection is a point.
- 17. When 2 planes intersect, their intersection is a line.
- 18. When a line and plane intersect, their intersection is a point.
- 19. Questions???
- 20. Classify each statements as true or false REMOTE TIME !
- 21. Question 1 PF ends at P
- 22. Question 2 Point S is on an infinite number of lines
- 23. Question 3 A plane has no thickness
- 24. Question 4 Collinear points are coplanar
- 25. Question 5 Planes have edges
- 26. Question 6 Two planes intersect in a line segment
- 27. Question 7 Two intersecting lines meet in exactly one point
- 28. Question 8 Points have no size
- 29. Question 9 Line XY can be denoted as XY or YX.
- 30. Horizontal Planes – Ceiling and Floor Horizontal Planes – Two sides horizontal and no sides vertical
- 31. Vertical Planes – Walls Vertical Planes – two sides are vertical
- 33. Group Practice Vertical line l intersects a horizontal plane M at point O l M O
- 34. Group Practice Horizontal plane Q and vertical plane N intersect
- 35. Group Practice Point P is not in Plane N. Three lines through point P intersect N in points A, B, and C.
- 36. True or False All points on a line are coplanar
- 37. True or False A line has one endpoint
- 38. True or False A point is named by a capital letter.
- 39. True or False Two lines intersect in two points.
- 40. True or False The edge of a plane is a line.