Question 60761
Solution:

Let the side of the square be “x”.
The perimeter of the square = 4x
Since the side of a equilateral triangle is 6 inches shorter than the side of a square, 
We can write it as,
The side of the equilateral triangle is x - 6
The perimeter of the triangle = (x - 6) + (x - 6) + (x - 6)
                              = 3(x - 6)
Given that the perimeter of the square is 36inches more than perimeter of the triangle.

The perimeter of the square = 36 + 3 (x -6)
                      4x    = 36 - 18 + 3x
                      4x    = 18 – 3x
                   4x -3x   = 18
                       x    = 18
                       x    = 18 inch

The length of the side of the square = 18inch