An arrangement of rods each of mass m and length l are welded (where ever required) to form a shape as shown.  The moment of inertia about an axis passing through point C and perpendicular to the plane of figure is:

$I=4\left(\frac{m{l}^2}{3}\right)+2\left[\frac{m{l}^2}{12}+m{\left(\frac{\sqrt{3}l}{2}\right)}^2\right]=3m{l}^2$

$\because$Moment of inertia of the rod about its end =$\frac{m{l}^2}{3}$

Moment of inertia of a thin rod about its centre and perpendicular to its length=$\frac{m{l}^2}{12}$

Moment of inertia of rods placed horizontally is given by =$\frac{m{l}^2}{12}+m{x}^2$ where x=$\frac{l\sqrt{3}}{2}$