Consider the equation, x2+y2−6x+12y+15=0 The centre is (3,-6) so, r=√9+36−15 =√30 The area is given by, A=π(√30)2 =30π The required equation has the radius twice of the area so, A′=60π πR2=60π R2=60 Thus, the equation of concentric circle is, (x−3)2+(y+6)2=60 x2+y2−6x+12y−15=0