| A | B |
|---|
| adjacent angles | two angles that share a ray |
| linear pair | two adjacent angles whose non-common sides are opposite rays |
| acute angle | an angle that measures more than 0 degrees but less than 90 degrees |
| complementary angles | two angles whose sum is 90 degrees |
| ray | a part of a line that has one endpoint and extends forever in one direction |
| similar | two figures that have the exact same shape, but not necessarily the same size |
| congruent | equal in measure |
| degree | a unit used to measure angles |
| angle | a figure formed by two rays with a common endpoint |
| straight angle | an angle that measures 180 degrees |
| right angle | an angle that measures exactly 90 degrees |
| vertex | the common endpoint of the two rays that form an angle |
| obtuse angle | an angle that measures more than 90 degrees and less than 180 degrees |
| vertical angles | non-adjacent angles with a common vertex formed by two intersecting lines |
| supplementary angles | two angles whose sum is 180 degrees |
| protractor | a tool used to measure angles |
