If the perimeter of the rectangle on the right is 24 m, and the length is 8, the width has to be 4, since 8+4+8+4=24. Since the scale factor is 24÷30=0.8 or 4/5, and the width of the rectangle on the right is 4, 4÷0.8=5, which is the width of the rectangle on the left.
Hope this helps! (P.S. I got it right on Edgenutiy, spelled wrong on purpose).
