Understanding Snell's Law with a Prism

[VitaX]

Homework Statement

[PLAIN]http://img854.imageshack.us/img854/6030/physicsch3364.png

Homework Equations

n₂θ₂ = n₁θ₁

The Attempt at a Solution

To be honest I'm lost from the get go, I'm having trouble with visualizing what part a exactly wants. Part B, I think is just the picture as is. But I'm confused about all the angles in the picture and just where exactly each applies. Any help appreciated.

 

[VitaX]

Nevermind, figured it out.