Find the angle between the circles given by the equations.
`x^2 + y^2 - 12x - 6y + 41 = 0,`
` x^2 + y^2 + 4x + 6y - 59 = 0.`

Find the angle between the circles given by the equations. x^2 + y^2 + 6x - 10y - 135 = 0, x^2 + y^2 - 4x - 116 = 0

Find the angle between the circles given by the equations. x^2 + y^2 + 6x - 10y - 135 = 0, x^2 + y^2 - 4x+14y - 116 = 0

Find the angle between the circles given by the equations x^(2)+y^(2)+6x-10y-135=0, x^(2)+y^(2)-4x+14y-116=0

If the angle between the circles x^2 + y^2 - 12x - 6y + 41 = 0 and x^2 + y^2 + kx + 6y - 59 = 0 is 45^@ find k.

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

Find k if the following pairs of circles are orthogonal. x^2 + y^2 - 6x - 8y + 12 = 0 , x^2 + y^2 - 4x + 6y + k = 0

Find the equation of the radical axis of the following circles. x^2 + y^2 -2x - 4y -1 = 0. x^2 + y^2 - 4x - 6y + 5 = 0 .

Find the equation of the radical axis of the following circles. x^2 + y^2 + 4x + 6y -7 = 0. 4(x^2 + y^2) + 8x + 12y - 9 = 0.

The equation of the common tangent at the point contact of the circles x^(2) + y^(2) - 10x + 2y + 10 = 0 , x^(2) + y^(2) - 4x - 6y + 12 = 0 is