1. Angle Relationships Common Necessary Vocabulary for Parallel and Intersecting Lines

2. Parallel Lines 2 lines are parallel if the lie in the same plane and do not intersect. PARALLEL LINES INTERSECTING LINES

3. Transversal A Transversal is any line that intersect two other lines. *Common Mistake: The two lines the transversal intersect do not have to be parallel *

4. Vertical Angles Vertical Angles are any pair of angles opposite each other at an intersection VERTICAL ANGLE PAIRS are ALWAYS congruent and equal in measure.

5. Straight Angle Pair Straight Angle Pairs are any pair of angles that form a straight line STRAIGHT ANGLE PAIRS are ALWAYS Supplementary (Adds up to 180°)

6. Corresponding Angles Corresponding Angles are angles that lie in the same position at different intersections *If two PARALLEL lines are cut by a transversal, then Corresponding Angles are Congruent *

7. Alternate Interior Angles Alternate Interior Angles are angles that lie on opposite sides of the transversal and on the Interior of the intersected lines *If two PARALLEL lines are cut by a transversal, then Alternate Interior Angles are Congruent *

8. Alternate Exterior Angles Alternate Exterior Angles are angles that lie on opposite sides of the transversal and on the Exterior of the intersected lines *If two PARALLEL lines are cut by a transversal, then Alternate Exterior Angles are Congruent *

9. Same Side Interior Angles Same Side Interior Angles are angles that lie on the same side of the transversal and on the Interior of the intersected lines *If two PARALLEL lines are cut by a transversal, then Same Side Interior Angles are Supplementary *