Complementary Angles

Complementary Angles

Complementary angles are angles that add up to 90° (See Diagram). The trigonometric ratios relating complementary angles (A and 90° –A) are as follows:

sin(90° – A) = cos(A)

cos(90° – A) = sin(A)

tan(90° – A) = cot(A)

Next: We will learn how find the trigonometric ratio of angles between 0° and 360° using the Unit Circle.