## Convex Quadrilateral Problem

Hi all,

Can someone help me with this problem about a convex quadrilateral?

Consider a convex quadrilateral ABCD as in this figure:

Known are: The two opposite sides AB ad CD, the two diagonals AC and BD, and the angle of sides AB and CD (in figure angle DPA or BPC)
What are the lengths of the sides AD and BC as a function of the above parameters?