Question 3
Given that $ABCD$ is a right-angled trapezium with $AB=BC$, $\angle ABC=\angle BCD=90^\circ$ and $E$ is a point on $BC$ such that $AE=AD$. If $AD=10$ and $BE=6$, find the length of $DE$.
Original choices: A. $\sqrt 2$; B. $\sqrt 3$; C. $2$; D. $2\sqrt 2$; E. $2\sqrt 3$.
Original choices: A. $\sqrt 2$; B. $\sqrt 3$; C. $2$; D. $2\sqrt 2$; E. $2\sqrt 3$.