MCQ
The radius of circle $x^2+ y^2 - 6x - 8y = 0:$
  • $5$
  • B
    $4$
  • C
    $3$
  • D
    $2$

Answer

Correct option: A.
$5$
The radius of circel $x^2+ y^2- 6x - 8y =0$ is
$=\sqrt{\text{g}^2+\text{f}-\text{c}}$
Here $g = -3, f = -4, c = 0$
$\Rightarrow\text{r}=\sqrt{(-3)^2+(-4)^2}$
$=\sqrt{9+16}$
$=\sqrt{25}$
$=5$

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