If you triple any of the 2 dimensions for a rectangle with a length if 3 inches and with of 5 inches, the perimeter would be the same for both ways you triple it. If both dimensions are halved then the rectangle would be half the size it originally was. If one of the dimensions is doubled, the perimeter would be 30 inches for both ways if you double one or the other. If both dimensions are doubled, it would be double the perimeter of if you were to only double one side, so it would be 60 in.