Circles

Circles:
The different situations that can arise when a circle and a line
are given in a plane.
So, let us consider a circle and a line PQ. There can be three possibilities given
in Fig. below:

The line PQ and the circle have no common point. In this case,
PQ is called a non-intersecting line with respect to the circle. In above Fig. (ii), there
are two common points A and B that the line PQ and the circle have. In this case, we
call the line PQ a secant of the circle. In Fig. 10.1 (iii), there is only one point A which
is common to the line PQ and the circle. In this case, the line is called a tangent to the
circle.
The tangent to a circle is a special case of the secant, when the two end
points of its corresponding chord coincide.