The area quadrupled. If the original square's perimeter is 20, each side length must be 5. The new square has double the perimeter, so it's 40. This means each side of the new square must be 10.
The formula for area in a square is base x height.
Square 1 area: 5x5 = 25
Square 2 area: 10x10 = 100
100/25 is 4, so the original square's area is 4 times smaller than the new square.