Q102 / 180 · KCET 2013 · Mathematics
The area of the circle having its centre at $(3,4)$ and touching the line $5 x+12 y-11=0$ is
- Correct answerA$16 \pi$ sq units
- B$4 \pi$ sq units
- C$12 \pi$ sq units
- D$25 \pi$ sq units
Solution
Given, centre of the circle is $(3,4)$.
Here, $P C=$ Length of perpendicular to the line $5 x+12 y-11=0$ from the centre of the circle.
$\begin{aligned}
\Rightarrow \quad P C &=\frac{|5(3)+12(4)-11|}{\sqrt{25+144}}=\frac{|15+48-11|}{\sqrt{169}} \\
&=\left|\frac{52}{13}\right|=4
\end{aligned}$

$5 x+12 y-11=0$ $\therefore$ Radius of circle $=P C=4$ Hence, required area of circle $=\pi$ (radius) ${ }^{2}$ $=\pi(4)^{2}=16 \pi$ sq units

$5 x+12 y-11=0$ $\therefore$ Radius of circle $=P C=4$ Hence, required area of circle $=\pi$ (radius) ${ }^{2}$ $=\pi(4)^{2}=16 \pi$ sq units
Hence, the correct answer is option: 'A'.