Top. In the family of special angles in Geometry, we come across many angles beside acute, obtuse, right, straight and other. In special angle, we will study about supplementary and complementary angles. Moreover vertical opposite angles, adjacent angles, interior and exterior all comes in the category of special angles. Complementary Angles: If the sum of two angles formed is 90 degrees, which means that if we add together two angles, we get the pair of Perpendicular Lines, then they are called complementary angles.