Three masses $(m=17\mathrm{.}5kg)$ are connected by massless rod of lengths $r_1=16\mathrm{.}5cm,r_2=22\mathrm{.}7cm$ and $r_3=41\mathrm{.}4cm.$ If this system rotates about the point all the rods connect, what will its moment of inertia be$?$