Question 21
In the following diagram, $AB$ is parallel to $DC$, $|AB|=6$ cm, $|AD|=17$ cm, $|DC|=10$ cm and $\angle DAB=90^\circ$. $E$ lies on $AD$ such that $BE$ is perpendicular to $EC$. If the area of the triangle $BEC=k\text{ cm}^2$, what is the largest possible value of $k$?
