1. Ch3.1_PointsLinesPlanes.notebook September 27, 2011
"Undefined" Terms
Chapter 3.1 Point
Points, Lines, and Planes Line ­ an infinite set of points extending in
2 opposite directions
Plane ­ infinite set of points in all directions
along a flat surface
Collinear Points ­ 2 or more points on the same line
Ray ­ A line with one endpoint
Coplanar Points ­ 2 or more points in the same plane
Line Segment ­ small section of a line
with 2 endpoints
Postulate 1
Postulates
Any 2 points make a unique line
Accepted as truth without proof

2. Ch3.1_PointsLinesPlanes.notebook September 27, 2011
Postulate 2 Postulate 3
3 non­collinear If 2 points lie in a plane,
points make a unique plane the line between them does too
Postulate 4 Postulate 5
"The Ruler Postulate"
2 planes intersect at a line
You can label a line with numbers
to determine coordinates and distance
­5 ­4 ­3 ­2 ­1 0 1 2 3 4 5
A C B D
Postulate 6 Example
Segment Addition
Add 2 segments together to get a If AC = 24, solve for x
bigger segment
x + 10 2x ­ 4
2 4
A B C
A B C D
C
A B D

3. Ch3.1_PointsLinesPlanes.notebook September 27, 2011
Example
On a number line, the coordinate of point S is ­5.
The length of ST is 12.
Give 2 possible coordinates of point T Page 107
5 ­ 18 all