#### Study Materials and Revision Notes for Ch 10 Circle Class 10th Maths

**Circle**

•

__: A circle is a locus of a point which moves in such a way that the distance from that point is always fixed.__

*Circle**•*

__The constant distance from the centre to the circumference of the circle.__

*Radius:*•

__A line which intersect the circle at two different points.__

*Secant:*•

__Any line segment joining the two points on the circumference of the circle.__

*Chord:*•

*The longest distance between the two points on the circumference of the circle. It is the longest chord.*

__Diameter:__
Here, AO is the radius of the circle and AB is the diameter of the circle.

**Tangent**

__•__

__: A line which touches the circle exactly at one point.__

*Tangent*• A line which touches the circle exactly at one point.

• The tangent at any point on a circle is perpendicular to the radius through the point of contact.

• In the above diagram l is tangent to the circle at point P. O is center, Then OP is perpendicular to l.

OP ⊥ l.

**Tangent drawn from an external point to a circle**

__Length of the tangent:__The length of the segment of the tangent from an external point P to the point of contact with the circle is called the length of the tangent from the point P to the circle.

**Theorem: The lengths of tangents drawn from an external point to a circle are equal.**

Two tangents are drawn from a point P, PA and PB.

PA=PB.