Fill in the blanks
Maximum number of common tangent of two intersecting circles is______.

The number of direct common tangents to two intersecting circles is "_______"

Number of common tangents of two concentric circle are

Find the maximum number of points of intersection of 6 circles.

Column I, Column II Number of straight lines joining any two of 10 points of which four points are collinear, p. 30 Maximum number of points of intersection of 10 straight lines in the plane, q. 60 Maximum number of points of intersection of six circles in the plane, r. 40 Maximum number of points of intersection of six parabolas, s. 45

Fill in the blanks Maximum value of 1/(sec theta) is______.

The maximum number of points of intersection of 8 straight lines is

How many maximum number of common tangents of two circles can be drawn intersecting at two different points ?

If two circles do not intersect or touch each other, then the maximum number of common tangents can be drawn is "_________"

The minimum number of common tangents drawn to two circles when both circles touch each other externally is___