Answer: Twice - once in the base plane and once in the vertical direction.
- A Three times, one for each coordinate plane involved
- B Only when all coordinates are positive as generally observed
- C Twice - once in the base plane and once in the vertical direction
- D Once, exactly as in two dimensions with an extra term appended
Correct answer: C. Twice - once in the base plane and once in the vertical direction
Explanation: The horizontal leg √(Δx² + Δy²) is found first, then combined with Δz in a second right triangle, giving √(Δx² + Δy² + Δz²).
Concept context
Coordinate axes and planes in space, octants, distance between two points, and the section formula
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