Question

The area (in square unit) of the circle which touches the lines $4 x+3 y=15$ and $4 x+3 y=5$ is

• A. $4\pi$
• B. $3\pi$
• C. $2\pi$
• D. $\pi$

Answer 1

Answer: (D)

$\pi$

Answer 2

Given lines are parallel.
$\therefore d=\frac{15-5}{\sqrt{4^{2}+3^{2}}}=\frac{10}{5}$
$\Rightarrow d=2=$ diameter of the circle
$\therefore$ Radius of circle $=1$
$\therefore$ Area of circle $=\pi r^{2}=\pi$ sq unit