| A | B |
|---|
| acute angle | measures between 0 and 90 degrees |
| adjacent angles | angles that have a common vertex and a common side, but no common interior points |
| angle | formed by two noncollinear rays or segments that have a common endpoint |
| angle bisector | a ray that divides an angle into two congruent angles |
| collinear | on the same line |
| complementary angles | their sum equals 90 degrees |
| concave | "pointing in" |
| congruent | "having the same measure" |
| convex | "pointing out" |
| coplanar | on the same plane |
| degree | 1/360 of a complete circle |
| linear pair | two adjacent angles whose sum is 180 degrees |
| midpoint | halfway between the endpoints of a segment |
| obtuse angle | measures between 90 and 180 degrees |
| perimeter | distance around a figure or object |
| perpendicular | intersects at a right angle |
| plane | a flat surface that extends indefinitely in all directions |
| line | extends indefinitely in two directions |
| point | a dimensionless location in space |
| polygon | a closed figure with three or more coplanar segment sides |
| ray | starts at a point and extends indefinitely in one direction |
| "regular" | convex, all sides congruent, all angles congruent |
| right angle | measures 90 degrees |
| segment bisector | divides a segment into two congruent pieces |
| supplementary angles | angles whose sum is 180 degrees |
| vertex | the common endpoint shared by the sides of an angle |
| vertical angles | nonadjacent angles formed by two intersecting lines |
| compound statement | formed by joining two or more statements |
| conjecture | an educated guess based on given or known information |
| conjunction | a compound statement joined by the word "AND" |
| counterexample | used to show a statement is false |
| disjunction | a compound statement joined by the word "OR" |
| negation | has the opposite meaning and truth value of the original statement |
| truth value | the truth or falsity of a statement |
