Answer: (2, 3, 6).
- A (2, 3, 6)
- B (1, 1.5, 3)
- C (4, 6, 12)
- D (2, 3, 7)
Correct answer: A. (2, 3, 6)
Explanation: The foot is 49·(2,3,6)/(2²+3²+6²) = 49·(2,3,6)/49 = (2, 3, 6).
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