Well, you can find the cross sectional area of the two curves.

The sine curve has equation:

The parabola has equation

y = ax(x-12)

Putting (6, 4), we get a = -1/9

Hence, equation of parabola:

Find the Area using:

Then, find the volume using

A is the cross sectional area and d is the depth of the prism.

The price will become trivial then.