So it can be concluded that a 20-meter-long rope can form a square.
Maximum value: perimeter ÷ 4 = side length
20÷4=5 (meters)
5×5=25(m？ )
Possibility:1491625 36 49 64 81 ...
2. The side length is 40m, so the original width is 40-2 = 38.
The original side length is 40m, or it can be said that the original side length is 40m38× 40 = 1520 (m? )-area