 #### Circles : Class 9th

If you notice,the second’s hand goes round the dial of the clock and its tip moves in a round path. This path traced by the tip of the second’s hand is called a Circle.

The figure above represents a circle.’A’ lies inside the circle,B lies outside the circle and C lies on the circle.
The circle has various interesting properties about which you can understand from Reference Notes.1. If you understand better by videos,Video Lecture 1 covers all the topics,proofs and questions.

Optional : To understand the proof of the theorem that only one unique circle passes through three non-collinear points,refer to Video lecture 2.

#### Circles : Class 10th

If you consider a circle and a line in a plane,there can be three possibilities: 1. 1)Non intersecting:The line and circle don’t touch.
2. 2)Intersecting at a single point:They have a single common point.
3. 3)Intersecting at two points

Second case is the special case where the Line act as the TANGENT to the circle. To know more about tangents and understand their various properties,refer to Video Lecture 3.

Now that you have understood the concepts of circles,please try the questions for practice from the link below