01. Tangents:
For any straight line we have only three possibilities: -
it doesn’t intersect the circle,
it intersects the circle at two different points and it touches the circle at just one point.
2. Secant:
When a straight line intersects the circle as two points it is known as secant.
3. Tangent:
When the straight line touches a circle at exactly one point, it is known as tangent to the circle at that point.
A circle can have infinite number of tangents.
There can be at most two tangents parallel to a secant.
The common point of the circle and the tangent is known as point of contact.
The tangent at any point of a circle is perpendicular to the radius through the point of contact.
Number of tangents to a circle:
i) There is no tangent to a circle passing through a point lying inside the circle.
ii) There is one and only one tangent to a circle passing through a point lying on the circle.
iii) There are exactly two tangents to a circle through a point lying outside the circle
Length of the segment of the tangent from an external point to the point of contact is length of the tangent. The lengths of tangents drawn from an external point to a circle are equal.
