| A | B |
|---|
| plane | a flat surface that continues infinitely in all directions |
| coplanar | points that lie on the same plane |
| line segment | an object consisting of two endpoints and all of the points between them |
| non-collinear points | points that do not lie on the same line |
| ray | an object with one endpoint that continues infinitely in one direction |
| point | an exact location in space with an indefinite shape and size |
| line | an object with no thickness that continues infinitely in two directions |
| non-coplanar | do not line in the same plane |
| opposite rays | two rays that begin at the same endpoint and extend in opposite directions |
| parallel lines | two lines that have the same slope |
| perpendicular lines | two lines that have slopes that are negative reciprocals of each other |
| postulate | a statement that is taken to be true |
| theorem | a statement that can be proven |
| midpoint | a point located exactly between the two endpoints of a line segment |
