First we have to find length of 1 side of the square. We can use formula for area of the square. A=a*a ==> [tex]A=a^2[/tex] where a is length of the side.
From this formula we can find
[tex]a= \sqrt{A} [/tex]
a=[tex] \sqrt{6561} =81 - 1 side[/tex]
Now we just have to multiply it by 4, because there are 4 sides.
81*4=324 - its the answer
