Prove that the radii of the circles `x^2 +y^2 = 4, 4x^2 + 4y^2 - 8x-24y+15=0 and x^2 + y^2 - 4y - 5 =0` are in arithmetic progression.

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

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.

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 point of tangency of the circles x^2+ y^2 - 2x-4y = 0 and x^2 + y^2-8y -4 = 0 , is

The point of tangency of the circles x^2+ y^2 - 2x-4y = 0 and x^2 + y^2-8y -4 = 0 , is

Common chord of the circles x^2+y^2-4x-6y+9=0, x^2+y^2-6x-4y+4=0 is

Prove that the centres of the three circles x^2 + y^2 - 4x – 6y – 12 = 0,x^2+y^2 + 2x + 4y -5 = 0 and x^2 + y^2 - 10x – 16y +7 = 0 are collinear.

Prove that the centres of the three circles (x^2 +y^2 −4x−6y−12=0) , (x^2 +y^2 +2x+4y−5=0) and (x^2 +y^2 −10x−16y+7=0) are collinear.