| A | B |
|---|
| right angle | A 90 degree angle. |
| vertex | common endpoint in an angle |
| intersecting lines | Lines that cross each other. |
| perpendicular lines | Two lines that cross each other to form a 90 degree angle. |
| acute angle | An angle less than 90 degrees. |
| obtuse angle | measures > 90 but < 180 degrees |
| straight angle (a line) | measures exactly 180 degrees |
| reflex angle | measures > 180 but < 360 degrees |
| ray | two of these form an angle |
| line | infinite number of points extending in both directions |
| number of degrees in straight line | 180 |
| adjacent angle | 2 angles that share a common vertex and ray |
| complementaryangles | 2 adjacent angles who sum is 90 degrees |
| supplementary angles | 2 adjacent angles whose sum is 180 degrees |
| linear pair of angles | adjacent angles that form a straight line |
| congruent | equal |
| vertical angles | angles across from each other when 2 lines intersect |
| unit of measure for all angles | degrees |
