The length of the rectangle is 15cm, and the width is 3 times less. Find the area of a square

The length of the rectangle is 15cm, and the width is 3 times less. Find the area of a square that has the same perimeter as the given rectangle.

Initially, we find the width of the rectangle, since it is known that it is three times less than the length, then denoting the width as x, we can solve the equation:
3x = 15, x = 5
We got that the width is 5 cm, then we find the perimeter of this rectangle:
P = 2 * (5 + 15) = 40 cm, since we know that the perimeter of both the rectangle and the square coincide, it is easy to find the side of the square, the length of the side of the square is 10 cm, then we find the area of the square:
S = 10 * 10 = 100 cm2