| A | B |
|---|
| acute angle | an angle with a degree measure less than 90 degrees |
| adjacent angles | two angles that lie in the same plane, have a common vertex and a common side, but no common interior points |
| angle | the intersection of two noncollinear rays at a common endpoint |
| angle bisector | a ray that divides an angle into two congruent angles |
| collinear | points that lie on the same line |
| complementary angles | two angles with measures that sum to 90 degrees |
| congruent | having the same measure |
| coplanar | points that lie on the same plane |
| line segment | a measurable part of a line that consists of two points called endpoints, and all the points between them |
| linear pair | a pair of adjacent angles whose non-common sides are opposite rays |
| midpoint | the point halfway between the endpoints of a segment |
| obtuse angle | an angle with degree measuring greater than 90 and less than 180 |
| perimeter | the sum of the lengths of the sides of a polygon |
| perpendicular lines | lines that form right angles |
| right angle | an angle with the measure of 90 degrees |
| segment bisector | a segment, line, or plane that intersects a segment at its midpoint |
| supplementary angles | two angles with measures that have a sum of 180 degrees |
| vertical angles | two non-adjacent angles formed by two intersecting lines |
