Q194 / 270 · NDA 2012 (Phase 2) · Mathematics
What is the perpendicular distance between the parallel $3 x+4 y=9$ and $9 x+12 y+28=0$ ?
- A$7 / 3$ units
- B$8 / 3$ units
- C$10 / 3$ units
- Correct answerD$11 / 3$ units
Solution
$3 x+4 y-9=0$\ldots(1)
$3 x+4 y+\frac{28}{3}=0$\ldots(2)
distance between parallel lines $=\frac{\left|\frac{28}{3}+9\right|}{\sqrt{3^2+4^2}}$
$\Rightarrow \frac{55}{15} \Rightarrow \frac{11}{3}$ units.
Hence, the correct answer is option: 'D'.