| A | B |
|---|
| point | shown as a dot and usually named with a capital letter |
| endpoint | a point at the end of a line segment or ray |
| line | a set of points that extends indefinitely in opposite directions |
| line segment | part of a line between two endpoints |
| ray | part of a line extending indefinitely from an endpoint in one direction |
| angle | two rays having the same vertex |
| vertex | another name for endpoint |
| complementary angles | two angles that measure 90 degrees together |
| supplementary angles | two angles that measure 180 degrees together |
| acute angles | angles that measure less than 90 degrees |
| obtuse | angles that measure more than 90 degrees but less than 180 degrees |
| right angles | angles that measure exactly 90 degrees |
| straight angles | angles that measure exactly 180 degrees |
