# complementary angles

Two angles are called of each other, if their sum is the right angle $\displaystyle\frac{\pi}{2}$, i.e. $90^{\circ}$.

For example, the acute angles of a right triangle are complement angles of each other, since the angle sum in any triangle is $180^{\circ}$.

The sine of an angle is equal to the cosine of the complement angle, and vice versa.

The tangent of an angle equals to the cotangent of the complement angle, and vice versa (provided that no one of the angles is a multiple of the straight angle).

 Title complementary angles Canonical name ComplementaryAngles Date of creation 2013-03-22 17:18:07 Last modified on 2013-03-22 17:18:07 Owner pahio (2872) Last modified by pahio (2872) Numerical id 7 Author pahio (2872) Entry type Definition Classification msc 51G05 Classification msc 51F20 Synonym complement angles Synonym complementary Related topic ExplementaryAngle Related topic SupplementaryAngles Related topic GoniometricFormulae Related topic ConvexAngle Related topic Explementary