I need to know how to (function name maybe) find the angle of a corner of a right triangle from the length of the 3 sides of a it.<

I do know how to do this with a calculator, I jsut don't know what it does, or what's its called in vb. (I tihnk what I'm looking for is like a... 'unsin' (sin(a) = 3 unsin(3) = a))