Mathematics · 3D Geometry

JEE Main 2025 — 22 January, Evening Shift — Question 9

The perpendicular distance, of the line x−12=y+2−1=z+32\frac{x-1}{2}=\frac{y+2}{-1}=\frac{z+3}{2} from the point P(2,−10,1)P(2,-10,1), is:

  1. Option A:

    6

  2. Option B:

    525 \sqrt{2}

  3. Option C:

    353 \sqrt{5}

    Correct
  4. Option D:

    434 \sqrt{3}

Answer: C

Step-by-step solution

x−12=y+2−1=z+32=λ\frac{x-1}{2}=\frac{y+2}{-1}=\frac{z+3}{2}=\lambda (let)

(2λ+1,−λ−2,2λ−3)(2 \lambda+1,-\lambda-2,2 \lambda-3)

∵PA→.n→=0\because \overrightarrow{\mathrm{PA}} . \overrightarrow{\mathrm{n}}=0

⇒(2λ−1)2+(−λ+8)(−1)+(2λ−4)2=0\Rightarrow(2 \lambda-1) 2+(-\lambda+8)(-1)+(2 \lambda-4) 2=0

⇒4λ−2+λ−8+4λ−8=0\Rightarrow 4 \lambda-2+\lambda-8+4 \lambda-8=0

⇒9λ−18=0⇒λ=2\Rightarrow 9 \lambda-18=0 \Rightarrow \lambda=2

∴A(5,−4,1)\therefore \mathrm{A}(5,-4,1)

∴AP=32+62+02=45=35\therefore\mathrm{AP}=\sqrt{3^{2}+6^{2}+0^{2}}=\sqrt{45}=3 \sqrt{5}

Solution figure

Answer key and solution verified before publishing.

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Exam
JEE Main 2025
Subject
Mathematics
Chapter
3D Geometry
Topic
Direction Cosines and Direction Ratios
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