In order to solve this problem you need to know: 1. The sum of the interior angles of a triangle adds up to 180°. 2. Supplementary angles add up to 180°. 3. The sum of the interior angles of a hexagon adds up to 720°. 4. Vertical angles are congruent and have the same measure. 5. The exterior angle of a triangle is the sum of the nonadjacent interior angles.
