If $a x^2+2 h x y-2 a y^2+3 x+15 y-9=0$ represents a pair of lines intersecting at $(1,1)$, then $a h=$

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

If $\left(\frac{1}{10}, \frac{-1}{5}\right)$ is the inverse point of a point $(-1,2)$ with respect to the circle $x^2+y^2-2 x+4 y+c=0$ then $c=$

If the equation of the circle lying in the first quadrant, touching both the coordinate axes and the line $\frac{x}{3}+\frac{y}{4}=1$ is $(x-c)^2+(y-c)^2=c^2$, then $c=$