A farmer has 80 meters of fencing to use to enclose a rectangular garden that has one side against a barn. a diagram of a rectangular garden built against a barn. the garden's length is labeled l meters long, and the garden's width is labeled w meters long. one of the sides of the garden measuring l meters long runs along the side of the barn. let l represent the length of the rectangular garden (in meters) and let a represent the area of the rectangular garden (in square meters).