Q220 / 270 · NDA 2021 (Phase 1) · Mathematics
The foot of the perpendicular drawn from the origin to the plane $x+y+z=3$ is
- A$(0,1,2)$
- B$(0,0,3)$
- Correct answerC$(1,1,1)$
- D$(-1,1,3)$
Solution
Given equation of plane $x+y+z=3$
Let point $P$ is $(0,0,0)$ and point $Q$ is the foot of perpendicular drawn from point $P$ on the plane.
Since, PQ is perpendicular to the plane, so direction ratio of line $\mathrm{PQ}\langle 1,1,1\rangle$.
$\therefore \quad$ Equation of line $P Q$,
$\frac{x-0}{1}=\frac{y-0}{1}=\frac{z-0}{1}=\lambda$
$\therefore(x, y, z)=(\lambda, \lambda, \lambda)$
As point Q lies on the given plane.
$\therefore \lambda+\lambda+\lambda=3 \Rightarrow \lambda=1$
Hence, Co-ordinate of point $\mathrm{Q}=(1,1,1)$.
Hence, the correct answer is option: 'C'.