### Home > GC > Chapter 5 > Lesson 5.3.3 > Problem 5-89

5-89.

Eugene wants to use the cosine ratio to find on this triangle.

Which angle should he use to write an equation and solve for

using the cosine ratio? Why?He'll need the adjacent side and the hypotenuse. To which angle is

adjacent?Set up an equation, and solve for

using cosine.