Enlarge the shape so that the sides are twice as long.
Calculate the area and perimeter for both shapes.
Compare the shapes.
The perimeter of the new shape is twice that of the original shape. The new shape's area is four times the area of the original shape.
Use the eTool below to enlarge the shape.
Click the link at right for the full version of the eTool: 3-28 HW eTool (Desmos)