| A | B |
|---|
| obtuse angle | an angle that measures more than 90 degrees and less than 180 degrees |
| counterclockwise | the direction in which you must turn to "open" an angle |
| acute angle | an angle that measures more than 0 degrees and less than 90 degrees |
| degree | the measurement unit for an angle defined by having a complete turn equal to 360 degrees |
| angle | a geometric figure formed by two rys with a common vertex |
| vertex | where two lines, segments or rays intersect |
| regular polygon | a polygon whose sides all have equal length and angles all have equal measure |
| protractor | the instrument calibrated to measure an angle |
| right angle | an angle that measures 90 degrees |
| ray | a portion of a line having a given endpoint and continuing to infinity in only one direction |
