Answer :

Perimeter = 2length + 2width
Since this is a square, we know that length and width are the same so the equation becomes:
Perimeter = 4 length
length = perimeter/4
length = 12ft / 4
length = 3 ft

Now we use the side length to find area.
Area = length * width
Since they are the same in a square:
Area = length²
Area = (3 ft)²
Area = 9 ft²

Therefore, the area is 9 square feet.
Even though, this should not be in the english category, the answer is 144 ft squared.