Reflect on this...Geometry Level 5
A square \(ABCD\) of side length \(k\) contains unit circles at each of corners \(B\) and \(D\) such that each circle is tangent to the square at precisely two points. A ray of light emanating from point \(A\) reflects off each circle and then returns to \(A\), creating a path in the shape of an equilateral triangle.
There is a unique value of \(k\) for which this scenario can occur. Find \(\lfloor 10000\cdot k \rfloor\).
Note: "Reflecting" means that the angle of incidence equals the angle of reflection.