Boxes hold various numbers of square-based prisms in a single column. The square base of each prism has a side length of 18 inches. The height of each prism, h, can be found using the function , where V is the volume of the prism. The total height of the box, b, can be found using the function b(h) = xh, where x is the number of square-based prisms in a specific box. Which function can be used to find the height of a box containing 4 square prisms, depending on the volume of the prisms?