AP EAMCET201921 Apr 2019Evening ShiftMathematicsCircleActual
If the lines x + 2 y - 5 = 0 and 2 x - 3 y + 4 = 0 lie along diameters of a circle of area 9 π , then the equation of the circle is
Options
- Ax 2 + y 2 - 2 x - 4 y - 4 = 0
- Bx 2 + y 2 + 2 x - 4 y - 4 = 0
- Cx 2 + y 2 + 2 x + 4 y - 4 = 0
- Dx 2 + y 2 - 2 x + 4 y - 4 = 0
Correct answer
A. x 2 + y 2 - 2 x - 4 y - 4 = 0
Step-by-step solution
Given: the lines x + 2 y - 5 = 0 and 2 x - 3 y + 4 = 0 lie along diameters of a circle of area 9 π We have π r 2 = 9 π ⇒ r 2 = 9 The intersection point of given lines will be center of the circle 2 x + 4 y = 10 - ( 2 x - 3 y = - 4 ) 7 y = 14 ⇒ y = 2 ,   x = 1 So the equation of circle is x - 1 2 + y - 2 2 = 9 ⇒ x 2 + y 2 - 2 x - 4 y - 4 = 0