Answer: 16.81
All the side lengths of the square are equal. And squares have 4 sides so if we just divide the perimeter by 4 then we can know how much each side length is.
16.4 / 4
4.1
Ok so each side length is 4.1 ! Now to find the area we just multiply the number twice.
4.1 * 4.1
16.81
There you go! We did it.
Now, make sure to hit the Brainliest button if I am correct!