A

David

Darling

complementary angles

right-angled triangle with complimentary angles

Angles α and β are complimentary.


Complementary angles are two angles whose sum is a right-angle (90°). For example, the angles adjacent to the hypotenuse of a right-angled triangle are complimentary angles. In the diagram, α and β are complimentary. Supplementary angles have a sum of 180°.