Eugene wants to use the cosine ratio to calculate $y$ for the triangle below. 

1. Which angle should he use to write an equation and solve for $y$ using the cosine ratio? Why?

   Hint (a):

   $\text{cos } \theta =\frac{\text{adj.}}{\text{hyp.}}$

   More Help (a):

   The side labeled $y$ is adjacent (next to) which angle?

2. Set up an equation, and solve for $y$ using cosine.

   Step (b):

   $\cos(\text{?})=\frac{y}{42}$