| A | B |
|---|
| adjacent angles | Two angles with a common vertex and side but no common interior points. |
| angle bisector | A ray that divides an angle into two angles that are congruent. |
| bisect | To divide into two congruent parts. |
| complement of an angle | The sum of the measures of an angle and its complement is 90 degrees. |
| complementary angles | Two angles whose measures have a sum of 90 degrees. |
| conclusion | The "then" part of an if-then statement. |
| deductive reasoning | Using facts, definitions, accepted properties and the law of logic to make a logical argument. |
| hypothesis | The "if" part of an if-then statement. |
| if-then statement | A statement with two parts: an "if" part that contains the hypothesis and a "then" part that contains the conclusion. |
| linear pair | Two adjacent angles whose noncommon sides are on the same line. |
| midpoint | The point on a segment that divides it into two congruent segments. |
| segment bisector | A segment, ray, line or plane that intersects a segment at its midpoint. |
| supplement of an angle | The sum of the measures of an angle and its supplement is 180 degrees. |
| supplementary angles | Two angles whose measures have a sum of 180 degrees. |
| theorem | A true statement that follows from other true statements. It can be proven to be true. |
| vertical angles | Two angles that are not adjacent and whose sides are formed by two intersecting lines. |
