The common point of the tangent and the circle is called the point of contact and the tangents is said to touch the circle at the common point.
Observe the tangents to the circle in the figures given below.

How many tangents can you obtain to the circle.in all?See the points of contact. Draw radii from the points of contact. Do you see any thing special about the angle between the tangents and radii at the points of contact. All appear to be perpendicular to the corresponding tangents.
Draw radii from the points of contact. Do you see any thing special about the angle between the tangents and radii at the points of contact. All appear to be perpendicular to the corresponding tangents.