Please Help:((( Please explain! :( What does S equal? (Explain!) Please asap:(((

So because this quadrilateral's sides are the same, S, this means that this is a square. With that in mind, the area of a square is [tex] A=x^2 [/tex], with x = sides. Since we have the area, we can solve for the side as such:
[tex] 1.69=S^2\\ \sqrt{1.69}=\sqrt{S^2}\\ 1.3=S [/tex]
In short, S = 1.3 km.