To the circle `x^(2)+y^(2)+8x-4y+4=0` tangent at the point `theta=(pi)/(4)` is

Let A be the centre of the circle x^(2)+y^(2)-2x-4y-20=0 . If the tangents at the points B (1, 7) and D(4, -2) on the circle meet at the point C, then the perimeter of the quadrilateral ABCD is

" If "x+y+7=0" is a tangent to the circle "x^(2)+y^(2)-4x-6y+k=0" then the point of contact is "

Circle x^(2) + y^(2) - 8x + 4y + 4 = 0 touches

Tangents drawn from the point P(1,8) to the circle x^(2) + y^(2) - 6x - 4y -11=0 touch the circle at the points A and B. The equation of the circumcircle of the triangle PAB is: