moment of inertia2

The distance from the center of each rod is given by

\\\tan 30 = \frac{d}{l/2} \\\Rightarrow d=\frac{l \tan 30}{2}=\frac{\sqrt{3}}{2}l

Moment of inertia of each rod is given by \\\frac{ml^2}{12}+m\left\{\frac{\sqrt{3}}{2}l \right\}^2 \\=ml^2\left\{\frac{1}{12}+\frac{3}{4} \right\}=\frac{10}{12}ml^2

Thus for three rods it will be \frac{5}{2}ml^2