Tessellate S.T.E.M.S (2019) - Mathematics - Category B - Set 1 - Objective Problem 4

Let $ABCD$ be a quadrilateral inscribed in circle with it's diagonals perpendicular to each other at $O$ , with $AB=17$ , $BC=7$ and $CD=4$ . Let the perpendicular from $O$ to $BC$ meet $AD$ at $P$ . Find $OP$ .

This problem is a part of Tessellate S.T.E.M.S. (2019)