You are asked to design a 1000m3 vertical steel tank for liquids. The client's specifications call for a cylindrical (flat) base and a conical top. The client also wants the radius and height of the conical part to be both equal to the radius of the cylindrical part. The thickness of the wall of the tank are to be kept within industrial safety regulations. What radius and height do you recommend for the cylindrical portion of the tank, so as to use the smallest amount of material possible