Moment of inertia of hollow rectangular section having outer depth 'D' and breadth 'B' and dimensions of inner rectangle are depth ādā and width 'b' about horizontal axis passing through centroid is:
1
\(\frac{BD^3}{12}\)
2
\(\frac{bd^3}{12}\)
3
\(\frac{{B{D^3}\;-\;b{d^3}}}{{12}}\)
4
\(\frac{{B{D^2}\;-\;b{d^2}}}{{12}}\)