Evaluating the composition of Functions using Right Triangles

The video tutorial explains how to evaluate the sine of the inverse cosine of sqrt(5)/5 by constructing a right triangle. It discusses the properties of inverse cosine, the creation of possible triangles, and the selection of the valid triangle in the first quadrant. The Pythagorean theorem is used to find the opposite side, leading to the final calculation of the sine value.

How do you find the opposite side of a triangle when given the hypotenuse and adjacent side?

Describe the process of using the Pythagorean theorem to find the length of a side in a right triangle.