A rectangular hole is to be cut in a wall for a vent. If the perimeter of the hole is 72 in. and the length of the diagonal is a minimum, what are the dimensions of the hole? Let the length and width of the hole be x and y, respectively, and let the length of the diagonal be D. Find an equation that describes the quantity to be minimized. (Type an equation.) The length of the diagonal is a minimum when the hole is (Type integers or decimals. Use ascending order.) by