Prove that the radii of the circles `x^(2)+y^(2)=1,x^(2)=y^(2)-2x-6y=6andx^(2)+y^(2)-4x-12y=9` are in AP.

Prove that the radii of the circles x^(2)+y^(2)=1,x^(2)+y^(2)-2x-4y-11=0andx^(2)+y^(2)-4x-6y-243=0 are in G.P.

Prove that the centres of the circles x^2+y^2=1 , x^2+y^2+6x-2y-1=0 and x^2+y^2-12x+4y=1 are collinear

Prove that the centres of the circles x^2+y^2=1 , x^2+y^2+6x-2y-1=0 and x^2+y^2-12x+4y=1 are collinear

The circles x^(2)+y^(2)-4x-6y-12=0 and x^(2)+y^(2)+4x+6y+4=0

The circle 4x^(2)+4y^(2)-12x-12y+9=0

The radical centre of the circles x^2+y^2=9, x^2+y^2-2x-2y-5=0 , x^2+y^2+4x+6y-19=0 is

The minimum radius of the circle which contains the three circles, x^(2)+y^(2)-4y-5=0,x^(2)+y^(2)+12x+4y+31=0 and x^(2)+y^(2)+6x+12y+36=0 is

Find the radical center of the circles x^2+y^2+4x+6y=19 ,x^2+y^2=9,x^2+y^2-2x-4y=5,

The radius of the circle x^(2) + y^(2) + 4x - 6y + 12 = 0 is

The centre of similutude of the circles x^(2)+y^(2)-2x-6y+6=0, x^(2)+y^(2)=1 is