Need to solve this but its hurting my head ...hehe

Calculate the diameter of a cylinder. The cylinder has a spherical top and a flat circular base .

The overall surface area is 2 M square.

The total height is 84 cm ... Thats it. I can solve for regular cylinder but with a spherical top im stuck....SA for sphere is 4 pi r square so half that and H= H-R but bit stuck any help welcome ...

Thanks