A metal silo is made by two basic shapes: a cylinder and a hemisphere. The cylinder part of the silo is 50' high and the radius of the silo is 16'. Using = 3.14, what is the circumference of the cylindrical part of the silo? C = A/ ft What is the lateral surface area of the cylindrical part of the surface area? L = A/ sq ft Using = 3.14, what is the surface area of the hemisphere top? S = A sq ft Assuming the base is made of concrete, how many total square feet are needed to make the silo? A sq ft of sheet metal.