Parallel lines with Transversal

A pair of angles that lie on opposite sides of the transversal and outside the parallel lines. : alternate exterior angles

A pair of angles that lie inside two parallel lines and on opposite sides of a transversal.--- : alternate interior angles

Two angles that make a straight line. They add up to 180 degrees. : supplementary angles

alternate exterior angles :

vertical angles :

supplementary angles :

supplementary-angles add to 180 degrees : same side exterior angles

congruent, angles are equal : vertical angles