The number of common tangents to two circles $x^2 + y^2 = 4$ and $x^2 + y^2 - 8x + 12 = 0$ is

The triangle $PQR$ is inscribed in the circle $x^2+y^2=25$. If $Q=(3,4)$ and $R=(-4,3)$,then $\angle QPR=$

$A$ circle passing through the point $(1,0)$ makes an intercept of length $4$ units on the $X$-axis and an intercept of length $2\sqrt{11}$ units on the $Y$-axis. If the centre of the circle lies in the fourth quadrant,then the radius of the circle is

Let a circle $C_1$ be obtained by rolling the circle $x^2+y^2-4x-6y+11=0$ upwards $4$ units along the tangent $T$ to it at the point $(3,2)$. Let $C_2$ be the image of $C_1$ in $T$. Let $A$ and $B$ be the centers of circles $C_1$ and $C_2$ respectively,and $M$ and $N$ be respectively the feet of perpendiculars drawn from $A$ and $B$ on the $x$-axis. Then the area of the trapezium $AMNB$ is:

The angle between two circles,each passing through the centre of the other,is

The circle $x^2 + y^2 - 4x - 4y + 4 = 0$ is...