| A | B |
|---|
| Midpoint | The point that divides a segment into two congruent segments. |
| Acute angle | An angle that measures greater than 0 but less than 90 degrees. |
| Vertical angles | Two angles whose sides form two pairs of opposite rays. |
| Supplementary angles | Two angles whose sum is 180 degrees. |
| Linear pair postulate | If two angles form a linear pair, then they are supplementary and their sum is 180 degrees. |
| Perpendicular lines | Two lines that intersect to form a right angle. |
| Segment bisector | Segment, ray, line, or plane that intersects a segment at its midpoint. |
| Congruent angles | Two angles that have the same measure. |
| Complementary angles | Two angles whose sum is 90 degrees. |
| Adjacent angles | Two angles that share a vertex and common side but have no interior points in common. |
| Linear pair | Two adjacent angles whose noncommon sides are opposite rays. |
| Obtuse angle | An angle that measures more than 90 degrees and less than 180. |
| Right angle | An gngle that measures 90 degrees. |
| Angle bisector | A ray that divides an angle into two congruent angles. |
| Theorem | A statement that must be proved to be true. |
| Postulate | A statement that is accepted as true without proof. |
| Collinear | Points, lines or segments that are on the same line. |
| Coplanar | Points, lines , or planes in the same plane |
| Converse | q implies p |
| Inverse | Not p implies not q |
| Contrapositive | Not q implies not p |
| Congruent Complements Theroem | If two angles are complementary to the same angle, then they are congruent. |
| Congruent Supplements Theorem | If two angles are supplementary to the same angle, then they are congruent. |
| Vertical Angles Theroem | If two angles are vertical angles, then they are congruent. |
