If a square field has an area of 479ft squared, what is the approximate length of the side of the field? (to the nearest foot)

In the problem, “if a square field has an area of 479ft squared, what is the approximate length of the side of the field”.
The given is:
Area = 479 ft
Formula: Since to get the area you have to have length and width hence the formula of area which is:
Area = length x width
We can derive the equation. As length x area = area2
Solution:
Length = area2
Length = square root of 479 ft squared
Length = 21.9 ft ”

Use photo math it

The second and fourth answer are correct