A parallelogram has diagonals of lengths 12 and 15 inches that intersect at an angle of 63.7 degrees. How long are the sides of the parallelogram?

Has something to do with law of sine...

2.) Assuming that the circles in the following figure are mutually tangent, find the lengths of the sides and the measures of the angles in triangle ABC. (I have a pic of the problem Thank you for your help?)