[-InnoXenT-]

$\displaystyle{I = \int r^2 \, dm}$

$\displaystyle{dm = gdv}$

$\displaystyle{= \int gr^2 dv}$

$\displaystyle{dv = r^2\sin{\theta}drd\theta d\phi }$

$\displaystyle{= \int_{0}^{2\pi}\int_{0}^{\pi}\int_{0}^{R} gr^4\sin{\theta} drd\theta d\phi}$