Question

If the given planes $ax + by + cz + d = 0$ and

$a'x + b'y + c'z + d' = 0$ be mutually perpendicular, then

• A. $\frac{a}{a'} = \frac{b}{b'} = \frac{c}{c'}$
• B. $\frac{a}{a'} + \frac{b}{b'} + \frac{c}{c'} = 0$
• C. $aa' + bb' + cc' + dd' = 0$
• D. $aa' + bb' + cc' = 0$

Answer 1

Answer: (D)

$aa' + bb' + cc' = 0$

Answer 2

It is a fundamental concept.