### Definition of Circle

A circle is a set of all points on a plane that are a fixed distance from a center.

## What is Radius?

The Radius is the distance from the center to the edge.

## What is Diameter?

The Diameter starts at one side of the circle, goes through the center and ends on the other side.

## What is Circumference?

The Circumference is the distance around the edge of the circle.

Circumference/Diameter = **π (pi)** = **3.14159**

## Area of a Circle

The area of a circle is π (Pi) times the radius squared, which is written :

A = π × r^{2}

Or, in terms of the Diameter: A = (π/4) × D^{2}

Let us understand this with the help of an example.

### What is the area of a circle with radius of 1.2 m?

A = π × r^{2}

A = π ×1.2^{2}

A = π × (1.2 × 1.2)

A = 3.14159… × 1.44 = 4.52 (up to 2 decimals)