Two lines are perpendicular if their direction ratios (a 1 ,b 1 ,c 1 ) and (a 2 ,b 2 ,c 2 ) satisfy:

a 1 a 2 + b 1 b 2 + c 1 c 2 = 0

📐 Mathematics · Three Dimensional Geometry · JEE

Two lines are perpendicular if their direction ratios (a₁,b₁,c₁) and (a₂,b₂,c₂) satisfy:

Answer: a₁a₂ + b₁b₂ + c₁c₂ = 0.

Correct answer: B. a₁a₂ + b₁b₂ + c₁c₂ = 0

Explanation: Perpendicular lines have zero dot product of direction vectors: a₁a₂ + b₁b₂ + c₁c₂ = 0.

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

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