1. 1.2 Points, Lines and Planes
Geometry
1.2 Points, Lines and Planes

2. 1.2 Basic Vocabulary all geometric figures consist of points Point
has no size , but is represented by a dot . P
all geometric figures consist of points

3. extends in 2 directions without ending
Line
extends in 2 directions without ending
has length, but no width or thickness
(like a point, the picture is symbolic)
Line d

4. Plane
extends in all directions without ending
like a floor or a wall
has length and width, but no thickness
(like a point and line, the picture is symbolic)
Plane K K

5. In Geometry, the terms point, line and plane are
accepted as intuitive ideas
not defined
used in definitions of other terms

6. Some More Definitions Space the set of all points
Collinear points points all in one line
Noncollinear points points not in one line

7. Still More Coplanar points points all in one plane
Noncoplanar points points not all in one plane

8. More about lines The intersection of two lines is a ______________?
Point

9. More about planes The intersection of two planes is a ______________?
Line

10. More about planes
The intersection of a plane and a line not on that plane is a
______________?
Point

11. Check for understanding
Turn to page 7 in your textbook
Examine the figures on the right side of the page
Let’s do Classroom Exercises (CE) #1-20 together (you have seen some of these before) Roll the dice!

12. P. 7 WE # 1-33 odd
P. 10 #40-46 Even
Look at Section 1.3
P. 14 #1-24 (4X) (1,4,8, etc…)