Mathematics - Geometry - Angles - Angle relationships (complementary, supplementary) - Complementary and Supplementary Angles
6 steps: (1) COMPLEMENTARY angles add to 90° (they 'complete' a right angle). Example: 35° and 55°. (2) SUPPLEMENTARY angles add to 180° (they 'supplement' to a straight line). Example: 110° and 70°. (3) Finding complement: 90° - angle. Complement of 40° = 50°. (4) Finding supplement: 180° - angle.