The sum of the length and width of a rectangle is 80 cm. Its perimeter is equal to that of a square. What is the area of the square?

The sum of the length and width of a rectangle is 80 cm. Its perimeter is equal to that of a square. What is the area of the square?

80 △ 2 = 40 (CM), 40 × 40 = 1600 (square cm); answer: the area of this square is 1600 square cm