| A | B |
|---|
| Acute Angles | Angles whose measure is less than 90 degrees. |
| Adjacent Angles | Angles that share a vertex and a side. |
| Angle Bisector | A ray that begins at the vertex and cut the angle into two congruent parts. |
| Collinear | Points all on the same line. |
| Complementary Angles | Two angles whose sum is 90 degrees. |
| Coplanar | Points all on the same plane. |
| Congruent Segments | Two segments that have exactly the same length. |
| Linear Pair | Two angles that are adjacent and whose noncommon sides are opposite rays. |
| Obtuse Angle | An angle whose measure is greater than 90 degrees. |
| Opposite Rays | Two rays that form a line. |
| Right Angle | An angle whose measure is 90 degrees. |
| Straight Angle | An angle formed by opposite rays and whose measure is 180 degrees. |
| Supplementary Angles | Two angles whose sum is 180 degrees. |
| Vertical Angles | Two nonadjacent angles formed by intersecting lines. |
| Angle | Formed by two noncollinear rays. |
| Line | One of the basic undefined terms of Geometry. Formed by an infinite number of collinear points. |
| Plane | One of the basic undefined terms of Geometry. Extend indefinitely in all directions and have no thickness. |
| Point | One of the basic undefined terms of Geometry. Have no dimension, are represented by a dot, and are named by capital letters. |
