Question

Direction ratios of two lines are a, b, c and $\frac { 1 } { b c } , \frac { 1 } { c a } , \frac { 1 } { a b }$. The lines are

• A. Mutually perpendicular
• B. Parallel
• C. Coincident
• D. None of these

Answer 1

Answer: (B)

Parallel

Answer 2

As $\frac { a } { ( 1 / b c ) } = \frac { b } { ( 1 / c a ) } = \frac { c } { ( 1 / a b ) }$ Hence lines are parallel.