A tangent is a line which touches the circle at only one point and does not enter the circle.
Watch this session on 'tangent to a Circle' and learn in detail about the following theorems and properties of a tangent:-
1) A Tangent is always perpendicular to the radius of a circle.
2) At one point on a circle only one tangent can be drawn.
3) Only two tangents will be parallel to a given chord or a secant.
4) Only two tangents can be drawn from a common external point.
5)Two tangents drawn from a common external point to a circle are equal in length.
These basic theorems on circles are explained logically in less than 10 minutes.