Answer:
4x - 36 feet
Step-by-step explanation:
The area A of a square whose sides are s units is given as
A = s * s
Given that the area A = x^2-18x+81, factorizing
A = x^2-9x-9x+81
A= x(x-9)-9(x-9)
A = (x-9)(x-9)
A = (x-9)^2
This means that the size of each side of the square courtyard is x-9 feet long
Recall that the perimeter P of a square whose side is s long is given as
P = 4s hence since the side of the courtyard is x - 9 feet, the perimeter of the courtyard
P = 4(x-9)
= 4x - 36 feet
