| A | B |
|---|
| Collinear | On the same line |
| Coplanar | In the same plane |
| space | boundless, 3-dimensional set of all points |
| segment bisector | segment, line, or plane that intersects a segment at its midpoint |
| angle bisector | ray that divides an angle into two congruent angles |
| congruent angles | angles with the same measure |
| angle | 2 noncollinear rays with a common endpoint |
| adjacent angles | 2 angles with common vertex, common side, but no common interior points |
| complementary angles | 2 angles with a sum of 90 degrees |
| supplementary angles | 2 angles with a sum of 180 degrees |
| intersection of 2 figures | set of points in both figures |
| linear pair | adjacent angles whose noncommon sides are opposite rays |
| midpoint | point that divides a segment into 2 congruent parts |
| obtuse angle | angle measuring between 90 and 180 degrees |
| opposite rays | 2 different collinear rays with a common endpoint |
| perpendicular lines | 2 lines intersecting at right angles |
| postulate | statement accepted as true without proof |
| ray AB | point A and all points on line AB that lie on the same side of A as B lies |
| right angle | angle with measure of 90 degrees |
| segment AB | endpoints AB and all points on line AB that lie between A and B |
| straight angle | angle with measure of 180 degrees |
| theorem | statement proved to be true |
| acute angle | angle with measure less than 90 degrees |
