A small square is constructed inside a square of area 1 by dividing each side of the unit square into \(n\) equal parts, and then connecting the vertices to the division points closest to the opposite vertices. Find the value of \(n\) if the the area of the small square is exactly \(\displaystyle\frac1{1985}\).
(1985AIME,連結有解答https://artofproblemsolving.com/ ... _Problems/Problem_4)