Question 553610
The formula for area of a square is {{{A=s^2}}} (area equals side squared) 
so in this case we have {{{200=s^2}}} so {{{s=sqrt(200)=sqrt(100)*sqrt(2)=10*sqrt(2)}}}

Now that we know the side, it is easy to find the perimeter. Just multiply the side by 4 so we get {{{40*sqrt(2)}}}