# Circle

## Definition

The locus of a moving point that maintains equidistant from a fixed point is called a circle.

Circle is a plane round shape figure and it is one of the most significant geometrical shapes in geometry. It is actually formed in two different ways.

1. A point which moves around another point with equidistant.
2. Joining the points which are located at equal distance from a point.

These two methods form round shape figure geometrically and it is called as circle. Here, you understand how exactly a circle is formed in geometric system.

## Construction

Consider a point in the plane and it is called as point

$O$

.

Consider another point in the plane and assume to call it as point

$P$

and it is located at

$r$

units’ distance from the point

$O$

.

Identify the points which are located at equal distance (

$r$

units) from the point

$O$

. Therefore, the distance from point

$O$

to point

$P$

is exactly equal to distance from point

$O$

to each surrounded point displayed in the below figure.

Now, join all the points and it forms a round shape figure, called circle.

$P$

is moved in round shape by maintaining equal distance from the point

$O$

. The point

$P$

is known as variable point because it represents all the points which are located at same distance from point

$O$

. The locus of the moving point gives a round plane figure and it is known as circle. The locus of variable point can be understood in this video tutorial.