The Geometry forum might be a better place, but I see nothing terribly wrong with putting it here. If one of the mods disagrees, they'll probably just move it.

There's a problem with your triangle. I'll show you when it comes up.

You have two approaches you can use, either the Law of Sines or the Law of Cosines. No matter what you do you will have to find one of the other angles in the triangle. It looks to me that you can only directly find angle C (then 180 - C - 62 = B). So let's find angle C using the Law of Sines:

sin(62)/9 = sin(C)/12

sin(C) = (12/9)*sin(62) = 1.17726

BUT sin(C) must be less than or equal to 1. Thus this triangle cannot exist. Was there a typo of some sort?

-Dan