Question

The distance between the planes $x + 2 y + 3 z + 7 = 0$ and $2 x + 4 y + 6 z + 7 = 0$ is

• A. $\frac { \sqrt { 7 } } { 2 \sqrt { 2 } }$
• B. $\frac { 7 } { 2 }$
• C. $\frac { \sqrt { 7 } } { 2 }$
• D. $\frac { 7 } { 2 \sqrt { 2 } }$

Answer 1

Answer: (A)

$\frac { \sqrt { 7 } } { 2 \sqrt { 2 } }$

Answer 2

Required distance = $\frac { 7 - \frac { 7 } { 2 } } { \sqrt { 1 + 4 + 9 } } = \frac { \sqrt { 7 } } { 2 \sqrt { 2 } }$ .