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=4ml23+2ml212+m3l22=3ml2∵Moment of inertia of the rod about its end =ml23Moment of inertia of a thin rod about its centre and perpendicular to its length=ml212Moment of inertia of rods placed horizontally is given by =ml212+mx2 where x=l32