The side of the square is 12cm 8mm less than the sum of the other three sides. Find the perimeter of this square.

Let’s solve this problem through the equation. Let x mm be the length of one side of the square. Since all sides of the square are equal, therefore the perimeter of the three sides is:

3 * x mm.

Since the side of the square is 12 cm 8 mm less than the sum of the other three sides, therefore:

x + 128 = 3 * x.

2 * x = 128.

divide both sides of the equation by 2:

x = 128/2;

x = 64.

The side of the square is 64 mm. Therefore, its perimeter is:

4 * 64 = 256 mm or 25.6 cm.

Answer: The perimeter of the square is 256 mm or 25.6 cm.