📐 Mathematics · Introduction to Three Dimensional Geometry · JEE

If a point P divides AB in the ratio k : 1 and lies on the XY-plane, then k is given by:

Answer: −z₁/z₂.

Correct answer: B. −z₁/z₂

Explanation: Setting the z-coordinate (kz₂ + z₁)/(k + 1) equal to zero gives kz₂ = −z₁, hence k = −z₁/z₂.

Concept context

Coordinate axes and planes in space, octants, distance between two points, and the section formula