Help solving for rate of angular change

[WRX200]

It'll be easier if I just enter this as an image:

http://img40.imageshack.us/img40/7366/prob13.jpg

I'm not even really sure where to begin. Any help on a good general direction of where to go would be much appreciated. I need to solve for an expression which describes θ(t) , and the change in angular velocity (dθ/dt)

[zachzach]

You can draw a right triangle and figure out theta in terms of x and y. Then all you need to do is find x in terms of t. Also, part a just wants theta as a function of time.