Answer :

Area of a Square: A = w²
Perimeter of a Square: P = 4w
(You can remove length because, in a square, length and with are the same)

w² = 120
w = √120
w ≈ 11

4w = 44
w = 11

The dimensions are ~10.9544 if you go by area
But they are likely looking for the answer 11, which is gotten from the Perimeter

The dimensions are 6 feet by 5 feet by 4 feet