If you don't know the sine rule, it is very easy. Let me tell you the sine rule first.
See the figure. Note that side a is opposite to angle A, side b is opposite to angle B, side c is opposite to angle C.
The sine rule is
It works for both all types of triangles - acute, obtuse and right angled.
If one angle and two sides are given, let A, a and b are given.
First find B, then find C and then c.