Plagued by Snell's law and geometry

[okgo]

I'm just having a horrendous time trying to figure this problem out. My geometry is really lacking.

http://www.screencast.com/users/trinhn812/folders/Jing/media/64c9342a-985a-4bb2-9e29-
98b5b5ebb1ad

 

[issacnewton]

url is not correct