A shaft carries four masses mA,mB,mC and mD of magnitude 30kg, 60kg, 50kg, and 25kg respectively, and revolving at radii 45mm, 50mm, 70mm, and 40mm in the same plane. The angular position of the masses mB,mC and mD are 90°,120° and 270° measured from the direction of mass mA. Find the magnitude and the position of the balancing mass required, if its radius of rotation is 60mm using the graphical method.