Q. Let $PS$ be the median of the triangle with vertices $P(2,\ 2)$, $Q(6,\ - 1)$ and $R(7,\ 3)$. The equation of the line passing through $(1,\ - 1)$ and parallel to $PS$ is
A) $2x - 9y - 7 = 0$
B) $2x - 9y - 11 = 0$
C) $2x + 9y - 11 = 0$
D) $2x + 9y + 7 = 0$
Explanation
(d)
Since, $S$ is mid point of $QR$
$\therefore\$ Coordinate of $S$ are
$\left( \frac{6 + 7}{2},\frac{- 1 + 3}{2} \right) = \left( \frac{13}{2},\ 1 \right)$
$\therefore\ \ Slope\ of\ PS = \frac{2 - 1}{2 - \frac{13}{2}} = - \frac{2}{9}$
[image:10_image13.emf]
The required equation which is
$passing\ throught\ (1,\ - 1)\ andslope - \frac{2}{9}\ ,\ is$
$y + 1 = - \frac{2}{9}(x - 1)$
$\Rightarrow 9y + 9 = - 2x + 2$
$\Rightarrow 2x + 9y + 7 = 0$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.