A storage shed is to be built in the shape of a box with a square base. It is to have a volume of 891 cubic feet. The concrete for the base costs $2 per square foot, the material for the roof costs $9 per square foot, and the material for the sides costs $4.50 per square foot. Find the dimensions of the most economical shed. Let x represent the length of one of the sides of the base and let G represent the cost of the shed. What is the objective function? C=11x2+% (Type an expression.) The interval of interest of the objective function is . (Simplify your answer. Type your answer in interval notation.) The length of one side of the shed's base is 9 ft. The height of the shed is 11 ft