The number of common tangents to the circles $x^2+y^2-4x-2y+k=0$ and $x^2+y^2-6x-4y+l=0$,having radii $2$ and $3$ respectively,is

What is the value of the mathematical constant $\pi$?

The length of the chord intercepted by the circle $x^2+y^2-6x+8y-5=0$ on the line $2x-y=5$ is equal to $L$ units. Find $L$.

If a circle $C,$ whose radius is $3,$ touches the circle $x^2 + y^2 + 2x - 4y - 4 = 0$ externally at the point $(2, 2),$ then the length of the intercept cut by circle $C$ on the $x-$axis is equal to

The line $ax + by + c = 0$ is a normal to the circle $x^2 + y^2 = r^2$. The portion of the line $ax + by + c = 0$ intercepted by this circle is of length:

The angle between the circles $x^2+y^2-4x-6y-3=0$ and $x^2+y^2+8x-4y+11=0$ is