The scale factor of rectangle jklm to rectangle qrst is . the perimeter of rectangle qrst is 12 units, and the perimeter of rectangle jklm is units. the area of rectangle qrst is units2, and the area of rectangle jklm is 128 units2. if proportional dimensional changes are made to a figure, then the perimeter will change by the scale factor, and the area will change by the scale factor.