Sine, Cosine, and Complementary Angles
Drag the diamond to change the rectangle’s size. Angles BAC and BAD are considered to be complementary because their measures add up to 90 degrees.
Observe how the sine and cosine of both complements change. How do the side ratios of each of the complements relate to each other? What other angles within the figure are complements to BAC and BAD? Do their sines and cosines relate the same way? Why is this?