[tex]\huge\boxed{\text{21 cm}}[/tex]
The area of a square is equal to the square of its side length. [tex]A=s^2[/tex]
Substitute in the known variable. [tex]441=s^2[/tex]
Now, find the square root of each side of the equation. [tex]\sqrt{441}=s[/tex]
Find the square root of [tex]441[/tex]. [tex]\boxed{21}=s[/tex]
