| A | B |
|---|
| Acute Angle | Angle with a measure greater than 0, but less than 90 |
| Angle Bisector | Ray that divides the angle into two congruent angles |
| Segment Bisector | A segment, ray, line, or plane that intersects a segment at its midpoint |
| Collinear Points | Points that lie on the same line |
| Coplanar Points | Points that lie on the same plane |
| Congruent Segments | Two segments are congruent if they have the same length |
| Congruent Angles | Two angles are congruent if they have the same measure |
| Midpoint of a Segment | The point that divides the segment into two congruent segments |
| Right Angle | Angle with a measure of 90 degrees |
| Obtuse Angle | Angle with a measure greater than 90 and less than 180 |
| Opposite Rays | On the line AB if C is between A and B, then ray CA and ray CB are opposite rays |
| Perpendicular Lines | Two lines are perpendicular if they intersect to form a right angle |
| Postulate | A statement that is accepted as true without proof |
| Theorem | A Statement that must be proved to be true |
