jasperE3 wrote: Let $M$ be a point inside a triangle $ABC$. The line through $M$ parallel to $AC$ meets $AB$ at $N$ and $BC$ at $K$. The lines through $M$ parallel to $AB$ and $BC$ meet $AC$ at $D$ and $L$, respectively. Another line through $M$ intersects the sides $AB$ and $BC$ at $P$ and $R$ respectively such that $PM=MR$. Given that the area of $\triangle ABC$ is $S$ and that $\frac{CK}{CB}=a$, compute the area of $\triangle PQR$. $Q$ is not defined.