Q. If lines $x = y = \mathcal{z}$ and $x = \frac{y}{2} = \frac{\mathcal{z}}{3}$, and third line passing through (1, 1, 1) form a triangle of area $\sqrt{6}$ units, then point of intersection of third line with second line will be

A) (1,2, 3)
B) (2, 4, 6)
C) $\left( \frac{4}{3},\frac{8}{3},\frac{12}{3} \right)$
D) None of these
Explanation

(b)
[image:12_image4.emf]
Let any point on second line be $(\lambda,\ 2\lambda,\ 3\lambda)$
$\cos\theta = \frac{6}{\sqrt{42}},\sin\theta = \frac{\sqrt{6}}{\sqrt{42}}$
$\Delta_{OAB} = \frac{1}{2}(OA)OB\sin\theta = \frac{1}{2}\sqrt{3}\ \lambda\sqrt{14} \times \frac{\sqrt{6}}{\sqrt{42}} = \sqrt{6}$
$\Rightarrow \lambda = 2$
So $B$ is (2, 4, 6)

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.