# sine and cosine of complementary angles.

- Author:
- abarkema@uni.edu

Angles BAC and BAD are considered to be complementary because their measures add up to 90 degrees. Drag the red diamond (Point B) to change the size of the rectangle.

Observe how the sine and cosine of both complements change. Which angles are complementary to each other? How are the ratios related to each other? What happens when you adjust the size of the rectangle?