Questions in circle

Select	Question
	The radius of a circle which touches y-axis at (0,3) and cuts intercept of 8 units with x-axis, is
	A point P moves in such a way that the ratio of its distance from two coplanar points is always a fixed number $(\ne 1)$ . Then its locus is
	The equation of the circumcircle of the triangle formed by the lines $y+\sqrt{3}x=6,\ y-\sqrt{3}x=6,$ and $y=0$ , is
	The equation ${{x}^{2}}+{{y}^{2}}+4x+6y+13=0$ represents
	The equation of a circle with centre $(-4,\ 3)$ and touching the circle ${{x}^{2}}+{{y}^{2}}=1$ , is
	The equation of the circle concentric with the circle ${{x}^{2}}+{{y}^{2}}-4x-6y-3=0$ and touching y-axis, is
	Locus of the centre of the circle touching both the co-ordinates axes is
	A line meets the coordinate axes in A and B. A circle is circumscribed about the triangle OAB. If m and n are the distance of the tangents to the circle at the points A and B respectively from the origin, the diameter of the circle is
	Radius of the circle ${{x}^{2}}+{{y}^{2}}+2x\cos \theta $ $+2y\sin \theta -8=0$ , is
	If the lines ${{l}_{1}}x+{{m}_{1}}y+{{n}_{1}}=0$ and ${{l}_{2}}x+{{m}_{2}}y+{{n}_{2}}=0$ cuts the axes at con-cyclic points, then