1. Point, Line, Plane Unit 1

2. Point A POINT is the most basic building block of geometry.
It has no size.
A precise location or place in space.
You represent a point with a dot, and you name it with a capital letter.

3. Line

4. Collinear Points
COLLINEAR – Points that are on the same line.

5. Line Segment

6. Coplanar Points
COPLANER –Points that are in the same plane.

7. Ray

8. Plane

9. Intersection

12. EXAMPLE 1
Name points, lines, and planes
1. a. Give two other names for PQ and for plane R.
b. Name three points that are collinear.
Name four points that are coplanar.
SOLUTION
Other names for PQ are QP and line n Other names for plane R are plane SVT and plane PTV.

13. EXAMPLE 1
Name points, lines, and planes
b. Points S, P, and T lie on the same line, so they are collinear. Points S, P, T,and V lie in the same plane, so they are coplanar.

14. GUIDED PRACTICE
for Example 1
Use the diagram in Example
Give two other names for ST .
Name a point that is not coplanar with points Q, S, and T.
ANSWER
TS, PT; point V

15. EXAMPLE 2
Name segments, rays
3. A. Give another name for GH .
B. Name all rays with endpoint J .
SOLUTION
a. Another name for GH is HG .
b. The rays with endpoint J are JE , JG , JF , and JH .

16. GUIDED PRACTICE
for Example 2
4. A. Give another name for EF
ANSWER FE
B. Are HJ and JH the same ray ?
C. Are HJ and HG the same ray? Explain.
ANSWER
No; the rays have different endpoints. Yes; points J and G lie on the same side of H.

17. EXAMPLE 3
Sketch intersections of lines and planes
5. A. Sketch a plane and a line that is in the plane.
B. Sketch a plane and a line that does not intersect the plane.
C. Sketch a plane and a line that intersects the plane at a point.
SOLUTION a. b. c.