Question

The equation of circle whose centre lies on 3x - y - 4 = 0 and x + 3y + 2 = 0 and has an area 154 square units is

• A. $x^2+y^2-2x+2y-47=0$
• B. $x^2+y^2-2x+2y+47=0$
• C. $x^2+y^2+2x-2y-47=0$
• D. None of these

Answer 1

The correct option is A $x^2+y^2-2x+2y-47=0$

Centre is (1, -1) (point of intersection of two given lines) and $\pi r^2=154\Rightarrow r=7$

$\because$ Equation of required circle is $(x-1{)}^2+(y+1{)}^2=49$
$\Rightarrow x^2+y^2-2x+2y-47=0.$