A rectangular box is to have a square base and a volume of 441 ft3. If the material for the base costs 44 cents per square foot, material for the top costs 10 cents per square foot, and the material for the sides costs 21 cents per square foot, determine the dimensions of the box (in feet) that minimize the total cost of materials used in constructing the rectangular box. Width of the base, x = :l feet Height of the box, y = :l feet