Which statements can be used to justify the fact that two right angles are supplementary? check all that apply. a. a right angle measures 90°. b. if two angles are complementary, the sum of the angles is 90°. c. if two angles are supplementary, the sum of the angles is 180°. d. a complementary angle is one-half the measure of a supplementary angle. e. a supplementary angle is twice the measure of a complementary angle.