Q. The radius of any circle touching the lines $3x - 4y + 5 = 0$ and $6x - 8y - 9 = 0$ is
A) 1.9
B) 0.95
C) 2.9
D) 1.45
Explanation
(b)
Given lines are $3x - 4y + 5 = 0$ and $3x - 4y - \frac{9}{2} = 0$, which are parallel to each other
$\therefore$ Perpendicular distance, $d = \left| \frac{5 + \frac{9}{2}}{\sqrt{3^{2} + 4^{2}}} \right| = \frac{19}{10}$
$\therefore$ Radius of circle$= \frac{d}{2} = \frac{19}{20} = 0.95$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.