Question 12
Let $O = (0, 0),$ $A = \left(\tfrac{1}{2}, 0\right),$ and $B = \left(0, \tfrac{\sqrt{3}}{2}\right)$ be points in the coordinate plane. Let $\mathcal{F}$ be the family of segments $\overline{PQ}$ of unit length lying in the first quadrant with $P$ on the $x$-axis and $Q$ on the $y$-axis. There is a unique point $C$ on $\overline{AB},$ distinct from $A$ and $B,$ that does not belong to any segment from $\mathcal{F}$ other than $\overline{AB}.$ Then $OC^2 = \tfrac{p}{q},$ where $p$ and $q$ are relatively prime positive integers. Find $p + q.$