Four masses are connected by 27.1cm long, massless, rigid rods. If massA=237.0g, massB=511.0g, massC=257.0g, and massD=517.0g, what are the coordinates of the center of mass if the origin is located at mass A?

^ I already got this part: x coordinate- 13.78 cm y coordinate- 13.67 cm

BUT PLEASE HELP ME WITH PART B!!!!!

b). What is the moment of inertia about a diagonal axis that passes through masses B and D.