# Revision Notes For CBSE Class 9 Math Chapter -10 Circles

In geometry, a circle is defined as a closed figure with a set of points in a plane at a specific distance from the centre. It is divided into two parts: an interior and an exterior.

The area of a circle is calculated by the given formulae: A = Ï€ r2

Where: A is the Area and r is the radius.

The properties of the circle are:

• The line passing through the centre of a circle is called a Diameter.
• The distance around the circle is called the Circumference.
• The distance from the centre to the circumference of a circle is called the Radius.

Notes about Class 9 Chapter 10 Maths-Circles is found below:

## Frequently asked Questions on CBSE Class 9 Maths Notes Chapter 10: Circles

### What is the definition of â€˜Diameterâ€™?

In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle.

### What is a â€˜Cyclic quadrilateralâ€™?

A cyclic quadrilateral is a quadrilateral drawn inside a circle. Every corner of the quadrilateral should touch the circumference of the circle.

### What is the meaning of a â€˜Segmentâ€™?

A segment refers to any of the parts into which a thing is divided or naturally separates.