Hi, Ptaverez1! :)
First we must length of an individual square; This can be achieved by using the formula for the area of a square:
![l^2](https://tex.z-dn.net/?f=l%5E2)
![l=Length](https://tex.z-dn.net/?f=l%3DLength)
Lets input the information we already know:
![l^2=42.25](https://tex.z-dn.net/?f=l%5E2%3D42.25)
Take square root.
![l=\sqrt42.25](https://tex.z-dn.net/?f=l%3D%5Csqrt42.25%20)
![l=6.5](https://tex.z-dn.net/?f=l%3D6.5)
The length of an individual square tile is
6.5 ft.
Since they're are 9 tiles and the porch in a square, I can conclude that the measurements for the porch are 3 tiles by 3 tiles (as 3*3=9; using the formula for the area of a square.)
Since the length of the porch is 3 tiles, we must multiply the individual tiles piece length by 3:
![3*6.5](https://tex.z-dn.net/?f=3%2A6.5)
![=19.5](https://tex.z-dn.net/?f=%3D19.5)
The formula for the perimeter of a square is:
![l*4](https://tex.z-dn.net/?f=l%2A4)
![l=length](https://tex.z-dn.net/?f=l%3Dlength)
Lets input the information we know:
![19.5*4](https://tex.z-dn.net/?f=19.5%2A4)
![=78](https://tex.z-dn.net/?f=%3D78)
The perimeter of the porch is 78 feet²
Hope this helps.
-Benjamin