August 31, 2012
1-1 Points, Lines, and Planes.
definition: known words to describe a new word
In geometry there are three undefined terms:
August 31, 2012
Point
August 31, 2012
Line
August 31, 2012
Plane
August 31, 2012
Collinear
August 31, 2012
Noncollinear
August 31, 2012
Coplanar
August 31, 2012
Noncoplanar
August 31, 2012
Segment
August 31, 2012
Ray
August 31, 2012
Opposite Rays
August 31, 2012
Postulate
August 31, 2012
Intersection:
August 31, 2012
How do 2 lines intersect? What is their
intersection? Sketch 2 intersecting lines.
August 31, 2012
How do 2 planes intersect? What is their intersection?
Sketch 2 intersecting planes.
August 31, 2012
Postulates:
1. Through any 2 pts. there is exactly one line.
2. Through any 3 noncollinear pts. there is exactly one plane
containing them.
3. If 2 pts. lie in a plane, then the line containing those pts. also
lies in the plane.
4. If 2 lines intersect, then they intersect in exactly one pt.
5. If 2 planes intersect, then they intersect in exactly one line.
August 31, 2012
August 31, 2012
E
Examples.
C
B
A
1. Name four coplanar points.
2. Name 3 lines.
D
August 31, 2012
Draw and label the following:
3. a segment with endpoints M and N.
4. opposite rays with common endpoint, T.
5. 2 lines intersecting in exactly 1 pt.