Area of a triangle.

Question

The area of a triangle $ABC$ is $144$.Denote the midpoint of $BC$ by $P$,of $AP$ by $Q$ and of $AC$ by $R$.Calculate the area of the triangle $PQR$.

I draw the picture but I do not have any idea to solve this.Please help me to solve this.

Thanks

Answer 1

$$S_{\Delta PQR}=\frac12S_{\Delta APR}=\frac14S_{\Delta APC}=\frac18S_{\Delta ABC}=18.$$