| A | B |
| A line that divides a line segment or angle into 2 equal parts | Bisector |
| lines that form 90 degree angles | Perpendicular Lines |
| nonintersecting lines | Parallel Lines |
| lines that meet at 90 degree angles | Intersecting Lines |
| a line that intersect two parallel lines | Transversal |
| angles on opposite sides of a transversal, inside the two parallel lines | Alternate Interior Angles |
| angles on opposite sides of a transversal, outside the two parallel lines | Alternate Exterior Angles |
| a 180 degree angle | Straight angle |