Find: Centre of mass of given system.

The figure lies in a 3d space

We write the coordinates of each particle

Sorry I accidentally posted earlier answer without completing it and don`t know to delete itWe write the co ordinates of each particleLet us assume the distance of each masa particle from axis is aFor each particle of mass m(a,a,0) , (a,0,0) , (0,0,0) , (0,a,0)For each particle of mass 2m(a,a,a) , (0,0,a) , (a,0,a) , (0,a,a)COM is given by={m(a,a,0) + m(a,0,0) + m(0,0,0) + m(0,a,0)+2m(a,a,a) + 2m(0,0,a) + 2m(a,0,a) + 2m(0,a,a)}÷12=(6a , 8a , 8a )÷12= (a/2 , 2a/3, 2a/3)