Can anyone help me on this problem dealing with capacitance and dielectrics?

Question

I have the answer but I just need to know the process:
You have a square parallel-plate capacitor of length 2L and seperation L/2. You have a dielectric slab of length L, width L, and thickness L/4. You can change the shape of the dielectric slab. However, the length must remain equal to the width, and the total volume must remain constant; you may only change the thickness. Show that if the thickness is h, then the capacitance is given by: C=[epsilon knot]L^2{4h^2/[L(k-1)+h] + L/2 - h }^-1. k is the dielectric constant kappa.

Answer 1

The answer IS the process, so if you have the answer, you have the process.

Answer 2

sorry