MathNet 2007-part-02 — 187 problems (EN–VI) Question 6

$ABCD$ is a convex cyclic quadrilateral. The diagonals $AC$ and $BD$ intersect at the point $E$. It is given that $AB = 39$, $AE = 45$, $AD = 60$ and $BC = 56$.
Determine the length of $CD$.