Периметр квадрата равен 124 см. Найдите площадь этого квадрата.

The perimeter of a square is 4 times the length of its side (P = 4a).
Given P = 124 cm, the side length is a = 124 cm / 4 = 31 cm.
The area of a square is the side length squared (A = a^2).
Therefore, the area is A = (31 cm)^2 = 961 cm^2.