Zaymiey

📐 Mathematics  ·  Three Dimensional Geometry  ·  JEE

The foot of the perpendicular from the origin to the plane 3x+4y+5z=25 is:

Answer: (1.5,2,2.5).

  • A (3,4,5)
  • B (1,2,3)
  • C (3/5,4/5,1)
  • D (1.5,2,2.5)

Correct answer: D. (1.5,2,2.5)

Explanation: Normal direction is (3,4,5). Point on normal from origin: (3t,4t,5t). Substitute: 9t+16t+25t=25, t=1/2. Foot = (3/2, 2, 5/2) = (1.5,2,2.5).

zxyOP (x, y, z)

Three mutually perpendicular axes x, y, z meeting at the origin O, with a point P located by its (x, y, z) coordinates.

Concept context

Lines and planes in 3D space, direction cosines, distances, and angles

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