| A | B |
|---|
| collinear | (points) on the same line |
| noncollinear | (points) not on the same line |
| point | undefined term - represented by a "dot", no actual size, named with a capital letter |
| line | undefined term, extends forever in 2 directions, straight, no thickness, determined by 2 points |
| plane | undefined term, a flat surface that extends forever, has no thickness, determined by 3 noncollinear points |
| coplanar | on the same plane |
| noncoplanar | not on the same plane |
| intersection of two figures | the set of points that are in both figures |
| How many points determine a plane? | 3 |
| How many points determine a line? | 2 |
| How many planes can contain 3 collinear points? | Infinitely many |
| Do two planes always intersect? | No |
| How many lines can pass through one point? | Infinitely many |
| Ray | half a line |
| opposite rays | 2 rays that share the same endpoint and form a line |
| Opposite rays | If point C lies on lline AB between A and B, then CA and CB are this |
| Defined term | Terms that can be described using known words. |
| Undefined term | A word without a formal definition. |
| Line segment | Part of a line that consists of two points, called endpoints, and all the points on the line between the endpoints. |
