Moment of inertia of a square prism

EDIT:
Can some1 help me solve this:

http://www.freeimagehosting.net/imag...4bbecc8847.png

Thanks in advance.

List of moments of inertia - Wikipedia, the free encyclopedia

steps involved to working this out would be appreciated, so I can understand how it is done.

OK I have worked out part (a):
I = integral y^2 . dA
= integral y^2.a.dy
= a.integral y^2 .dy from -b/2 to b/2
=a. [y^3/3] from -b/2 to b/2
= a.b^2 / 12

can sum1 confirm this and try continue with part (b). Thanks.