The question above makes use of the concept of ratio and proportion in a form of scaling. If we let x and y be the true length and width, the equations that best describe them are, 0.5 cm / 1 inch = 2.5 cm / x in ; x = 5 in 0.5 cm / 1 inch = 4.75 cm / y in ; y = 9.5 in Therefore, the true length and width of Rueben's flag is 5 in and 9.5 in, respectively.