Question

The angle between the straight lines $\frac { x + 1 } { 2 } = \frac { y - 2 } { 5 } = \frac { z + 3 } { 4 }$ and $\frac { x - 1 } { 1 } = \frac { y + 2 } { 2 } = \frac { z - 3 } { - 3 }$ is

• A. $45 ^ { \circ }$
• B. $30 ^ { \circ }$
• C.
• D. $90 ^ { \circ }$

Answer 1

Answer: (D)

$90 ^ { \circ }$

Answer 2

$\theta = \cos ^ { - 1 } \frac { ( 2 + 10 - 12 ) } { \sqrt { 4 + 25 + 16 } \sqrt { 1 + 4 + 9 } } = \cos ^ { - 1 } ( 0 )$ ⇒ $\theta = 90 ^ { \circ }$.