# Tangents of a Circle

- Author:
- Ku, Yin Bon (Albert)

- Topic:
- Circle

## Tangent properties

Given a circle, a line is said to be a

**tangent**to the circle if the line intersects the circle at exactly one point i.e. it "touches" the circle. In the following diagram, the lines through point A and B are tangents to the circle.he following are the basic properties of tangents that you should know in your high school:

## Tangent of a circle through a given point

Given a circle centered at O and points A and P such that A lies on the circle and P is outside of the circle. Construct the tangents to the circle through points A and P as shown in the applet below.

**Note**: What can you say about the locus of the point that forms a right-angled triangle with O and P?