6' A rectangular tank with a square base, an open top, and a volume of 21436 ft3 is to be constructed of sheet steel. Find the dimensions of the tank that has the minimum surface area. Let s be the length of one of the sides of the square base and letA be the surface area of the tank. Write the objective function. A: {Type an expression} The interval of interest of the objective funotion is {Simplify your answer. Type your answer in interval notation.) The tank with the minimum surface area has a height of it and a square base with a sidelength of ft