Vectors in Space · Hard problem

A parallelogram-shaped kite is braced by two rigid ribs represented by vectors $\mathbf u$ and $\mathbf v$, with $\lVert\mathbf u\rVert = 6$ ft, $\lVert\mathbf v\rVert = 5$ ft, and the angle $\theta$ between the ribs satisfying $\cos\theta = \tfrac13$. Find the area of the kite's sail (the parallelogram spanned by the ribs).