I would use the Law of Cosines to find the sizes of the angles. (Or, at least two of them, you can subtract from 180o to find the third angle.)
Knowing these, you can find the answers.
Find the size of angle(C) first; so, if you want to find the size of angle(A) or angle(B) by using the Law of Sines, you can do so.
You won't get the correct answer for angle(C) if you use the Law of Sines to try to find it.