22 terms

# Geometry Chapter 1

###### PLAY
Postulate 5
a line contains at least two points; a plane contains at least three points not all in one line; space contains at least four points not all in one plane
Postulate 6
Through any two points there is exactly one line
Postulate 7
Through any three points there is at least one plane, and through any three noncollinear points there is exactly one plane.
Postulate 8
If two points are in a plane, then the line that contains the points is in that plane
Postulate 9
if two planes intersect, then their intersection is a line
Theorem 1-1
if two lines intersect, then they intersect in exactly one point
Theorem 1-2
Through a line and a point not in the line there is exactly one plane.
Theorem 1-3
If two lines intersect, then exactly one plane contains the lines.
Segment
Two points on a line and all points in between them.
Ray
all points on segment AC and all points P such that c is between A and P
Opposite Rays
given 3 collinear points R,S,T,- if S is between R and T, SR and ST are opposite Rays
Length
Distance Between Endpoints of a Segment.
Ruler Postulate
1. The points on a line can be paired with the real numbers in such a way that any tho points can have coordinates 0 and 1. 2. Once a coordinate system has been chosen in this way , the distance between any two points equals the absolute value of the differences of their coordinates.
If B is between A and C, then AB+BC=AC
Congruent
Having the same size and shape
Congruent Segments
segments that have equal lengths
Midpoint of a Segment
The point that divides the segment into two congruent segments
Bisector of a Segment
a line, segment, ray, or plane that intersects the segment at its midpoint