Question 10
Square $ABCD$ has side $9$ cm. Points $M,N,P,Q$ lie on $AB,BC,CD,DA$, with $AM=BN=CP=DQ=3$ cm. Let $E,H$ be the intersections of $AC$ with $MQ,NP$, respectively, and $F,K$ the intersections of $BD$ with $MN,PQ$. Find the area of square $EFHK$.
