However, I will give you one hint (I managed to find a satisfactory solution using this): In a cyclic quadrilateral, angles opposite to each other are supplementary. Another way of saying this is that any two angles that lie along the same diagonal are supplementary. Thus, to solve this problem, you'll need to "define" which angles of A,B,C and D are supplementary (unless you're provided with an image to which we do not have access).
Give it another shot and post your work! When you post your work, it makes it easier to point out any mistakes you might have made.
I hope you understand our policy on assignments that count for grades, and I hope this helps give you additional insight on how to tackle your problem!