Parallel Lines and Transversas

vertical angles

Angles opposite one another at the intersection of two lines. These angles are congruent. Examples: Angle 1 and Angle 3 are vertical angles Angle 8 and Angle 6 are vertical angles

same side exterior angles

Exterior angles on the same side of the transversal cutting across 2 parallel lines. These angles are supplementary. Example: Angle 2 and Angle 8 are same side exterior and their sum is 180 degrees

same side interior angles

If the angles are on same side of the transversal and inside the 2 parallel lines then their sums ARE SUPPLEMENTARY. Example: Angle 3 and angle 5 are same side interior and their sum is 180 degrees

alternate exterior angles

If two parallel lines are cut by a transversal, then the alternate exterior angles are congruent. Example: angle 1 and angle 8 are alternate exterior angles

alternate interior angles

If two parallel lines are cut by a transversal, then the alternate interior angles are congruent. Example: angle 3 and angle 6 are alternate interior

corresponding angles

A pair of angles which are on the same side of the transversal, one must be interior, one must be exterior, and they must be nonadjacent. Corresponding angles are supplementary and are only formed when the lines are parallel. Example: Angle 3 and Angle 7 are corresponding Angle 2 and Angle 6 are corresponding

linear pair

Adjacent, supplementary angles. Excluding their common side, a linear pair forms a straight line. Examples: Angle 1 and Angle 4 are a linear pair. Angle 5 and Angle 6 are a linear pair. Angle 3 and Angle 4 are a linear pair.