Geometry: Area of Trapezoid Circumscribed About A Circle

[Yuki]

Hiii, this is a problem that I have encountered and I need help ASAP.
This is the figure:
http://img404.imageshack.us/img404/1120/mathhelpppp6yk.gif
Thanks a lot!


P.S. I apologize for posting at wrong forum

 

[robphy]

Some hints were given here: https://www.physicsforums.com/showthread.php?t=116986

 

[Yuki]

Thanks! T.T I couldn't find the thread, I thought my post was deleted because I posted in wrong forum.. Thanks a lot =D ><