Find the perimeter of the square if it is 18 cm larger than its side?

Let us denote the length of the side of this square by x.
Since the perimeter of any square is equal to the length of the side of this square, multiplied by 4, then the perimeter P of this square is:
P = 4 * x.
According to the condition of the problem, the perimeter of this square is 18 cm larger than the side of this square, therefore, we can draw up the following equation:
4 * x = x + 18.
We solve the resulting equation and find the side length of this square:
4 * x – x = 18;
3 * x = 18;
x = 18/3:
x = 6 cm.
Knowing the side length of a given square, we find its perimeter:
P = 4 * x = 4 * 6 = 24 cm.
Answer: the perimeter of this square is 24 cm.