When you double the dimensions of a polygon, the scale factor is two but if you triple it, its scale factor is three. The perimeter of a one by one polygon is four, but if you double the dimensions, the perimeter is eight, but if you triple it, it is twelve. The area of a one by one polygon is one, but if you double the dimensions of the polygon the area is four, but if you triple the dimensions it would be nine. You multiply the scale factor once for perimeter and twice for the area.