rotation 7

Assume that the centre of mass of a boy crouching in a little swing has been raised to 1.2m.The boy has his centre of mass at 3.7m from the pivot of the swing while he is in crouched position.The swing is released from bottom rest and at the bottom of the arc the boy stands up instantaneously,thus raising his centre of mass 0.6m.Find the height of his centre of the mass at the top of the arc.