## What are Complementary Angles:

Complementary angles are those angles that together add up to 90 degrees or 90º. ## Calculation of complementary angles

To calculate the complementary angle of a specific angle you only need to subtract 90 minus the known angle, for example, to know the complementary angle of a 65º angle we must do the following subtraction: 90 - 65 = 25. This means that the complementary angle the 65º angle is a 25º angle.

Similarly, adjacent complementary angles are those that share a vertex and added together give rise to right angles, that is, 90º angles.

## Characteristics of complementary angles

It is important to know complementary angles because they are found in many forms in nature and in physical phenomena. Complementary angles are used in architecture, construction, physiognomy, etc.

Through the knowledge of the complementary angles a spectrum of trigonometric notions is derived, such as, for example, the notion that the sum of the internal angles of a right triangle gives 180 degrees since it is composed of a 90 degree angle plus two angles complementary treble which adds up to 180 degrees.