| A | B |
| parallel | 2 lines in the same plane that do not intersect |
| perpendicular | 2 lines which intersect at 90˚ |
| vertical angles | opposing angles formed when 2 lines intersect |
| interior angles | angles inside parallel lines cut by a transversal |
| exterior angles | angles outside parallel lines cut by a transversal |
| alternate interior angles | pair of angles inside parallel lines on opposite sides of the transversal |
| alternate exterior angles | pair of angles outside parallel lines on opposite side of the transversal |
| transversal | a line which intersects 2 other lines |
| consecutive interior angles | angles on one side of the transversal inside the parallel lines |
| corresponding angles | angles on the same side of the transversal at the same relative location |