Vectors in Space · Challenge problem

A parallelepiped has edge vectors $\mathbf a = (1, 1, 0)$, $\mathbf b = (0, 2, 1)$ and $\mathbf c = (1, 0, 3)$ at one vertex. Taking the face spanned by $\mathbf a$ and $\mathbf b$ as the base, find the height of the parallelepiped.