Moment of inertia of a body about any axis is equal to the product of the area of the body and square of the distance of its centroid from that axis.

$Unit-mm ^{4}, \mathrm{cm}^{4}, \mathrm{m}^{4}$

$MI for Square =\mathrm{I}_{\mathrm{xx}=} \mathrm{I}_{\mathrm{yy}}=\frac{b d^{3}}{12}=\frac{b^{4}}{12}$

$MI for Quarter Circle =\mathrm{I}_{\mathrm{xx}=} \mathrm{I}_{\mathrm{yy}}=0.055 \mathrm{R}^{4}$