The radius of the circle $x^2 + y^2 + 4x + 6y + 13 = 0$ is

If a circle of radius $3$ passes through the point $(7,3)$ and has its centre on the line $x-y-1=0$,then its equation among the following is

The centre of the circle $r^2-4r(\cos \theta+\sin \theta)-4=0$ in Cartesian coordinates is

The equation of a circle passing through the point $(4, 5)$ and having the centre at $(2, 2)$ is

If $z=x+iy$,then the centre of the circle $\left|\frac{z-3}{z-2i}\right|=2$ is

If the equation of the circle passing through the point $(8,8)$ and having the lines $x+2y-2=0$ and $2x+3y-1=0$ as its diameters is $x^2+y^2+px+qy+r=0$,then $p^2+q^2+r=$