Tangents to a Circle
* A line that touches a circle at only one point is called a tangent to the circle.
* The point where a tangent touches a circle is called its point of contact.
* Only one tangent can be drawn at any given point on a circle.
* The tangent at any point on a circle is perpendicular to the radius drawn to its point of contact.
* Only two tangents can be drawn to a circle from any point lying outside it.
* Tangents drawn to the circle from an external point are equal in length.