Remember that the formula used to calculate the area of a square is:
[tex]A=s^2[/tex]Where s is the lenght of the side of the square.
This way,
[tex]20=s^2[/tex]Solving for s,
[tex]20=s^2\rightarrow s=\sqrt[]{20}[/tex]Therefore, the lenght of a side of the square is:
[tex]\sqrt[]{20}\text{ m}[/tex]Answer: Option B
