| A | B |
|---|
| perpendicular | two line segments, lines, or rays that meet or cross and form at least right angle |
| line of symmetry | a line that divides a figure into 2 congruent parts |
| rotational symmetry | a figure that matches itself after a 1/2 turn or less |
| perimeter | the distance around a polygon |
| area | the number of square units it takes to cover a polygon |
| acute angle | an angle that measures less than 90 degrees |
| obtuse angle | an angle that measures more than 90 degrees |
| straight angle | an angle that measures 180 degrees |
| protractor | an instrument used to measure angles |
| ray | part of a line that has a beginning point but does not have an endpoint |
