Where to sit in a theatre bonus problem

[nickto21]

Hello all,
I'm in Calculus 2, and I was given a problem for bonus points, which I desperately need. It has to do with the best place to sit in a movie theatre. The problem is long, and has a diagram, so I've attached an image of the problem to this post.
I have no real clue where to start with this problem, so a push in the right direction is greatly appreciated.
Thanks,
Steve

 

[daudaudaudau]

You can get started using the law of cosines

http://en.wikipedia.org/wiki/Law_of_cosines" [Broken]

 

[DavidWhitbeck]

Do you have a graphing calculator? They want to use either that or something like mathematica or MATLAB on the computer.