If the circles $x^2+y^2-16 x-20 y+164=r^2(r>0)$ and $x^2+y^2-8 x-14 y+29=0$ intersect in two distinct points, then the maximum possible integral value of $r$ is

If the circle $x^2+y^2-6 x-12 y+1=0$ cuts another circle $C$ orthogonally and the centre of the circle $C$ is $(-4,2)$, then its radius of

The equation of the incircle of the triangle formed by the lines $x=0, y=0$ and $3 x+4 y-24=0$ is

If two tangents are drawn from the point $P\left(\frac{\pi}{4}\right)$ on the circle $x^2+y^2=4$ to the circle $x^2+y^2=1$, then the slopes of the tangents are