Perimeter of the rectangle = 2(3x+6) + 2(x-1)
= 6x + 12 + 2x - 2
= 8x + 10
Perimeter of the square = 4(x+6) = 4x + 24
The perimeters are yhe same, so:
8x + 10 = 4x + 24
8x - 4x = 24 - 10
4x = 14
x = 3.5
Now calculate the perimeter of any plot:
Perimeter of the square = 4x + 24 = 4*3.5 + 24 = 14 + 24 = 38 ft
Answer is 38 ft.