Suppose rectangles X and Y are similar. The dimensions of rectangle X are 5 centimeters by 7 centimeters. The area of rectangle Y is 140 square centimeters. What are the dimensions of rectangle Y?
The ratio of the sides = 5/7.
The factors of 140 = 2 * 2 * 5 * 7
How can you combine those into just two factors (length and width) so their ratio = 5/7?