There are two squares of different sizes. The difference in circumference is 20cm and the difference in area is 75cm. What is the area of the big square?

There are two squares of different sizes. The difference in circumference is 20cm and the difference in area is 75cm. What is the area of the big square?

20 △ 4 = 5cm, side length difference 5cm
75-5 × 5 = 50 square centimeter
Side length of small square: 50 △ 2 △ 5 = 5cm
Side length of large square: 5 + 5 = 10 cm
Then the area of the large square is: 10 × 10 = 100 square centimeters