5. In a square $A B C D$, let $P$ be a point on the side $B C$ such that $B P=3 P C$ and $Q$ be the mid-point of $C D$. If the area of the triangle $P C Q$ is 5 , what is the area of triangle $Q D A$ ?
(a) 5;
(b) 10 ;
(d) 20 ;
(e) 25 .
5 Ans: (d).
The two triangles are similar and $\frac{P C}{Q D}=2$. Hence Area $Q D A=4 \times$ Area $P C Q=20$.