| A | B |
|---|
| acute angle | measures less than 90 degrees |
| acute triangle | triangle with 3 acute angles |
| right angle | measures 90 degrees |
| right triangle | triangle with a right angle |
| obtuse angle | measures more than 90 degrees |
| obtuse triangle | triangle with an obtuse angle |
| protractor | devise to measure angles |
| straight angle | measures 180 degrees |
| complementary angles | angles that measure 90 degrees |
| supplementary angles | angles that measure 180 degrees |
| isosceles triangle | 2 sides are congruent |
| scalene triangle | no sides are congruent |
| equilateral triangle | 3 sides are congruent |
| perpendicular lines | form right angles |
| parallel lines | do not intersect |
| perimeter | distance around a figure |
| circumference | distance around a circle |
| pentagon | 5-sided polygon |
| hexagon | 6-sided polygon |
| octagon | 8-sided |
