### Theory:

**A circle**:

When all the points on a plane is at a fixed distance from the fixed point is called a circle.

The line that joins the centre of the circle and any point on the circle is called the radius.

A circle acts as a closure to all the points on the plane.

This closure can be classified into three categories:

**1.**The points that are interior to the circle.

**2.**The points that are on the circle.

**3.**The points that are outside the circle.

**Some other components of the circle**:

**A chord**:

When a line segment connects any two points on the circle, then it is called a chord.

**A diameter**:

The line segment that passes through the centre of the circle connecting two definite points on the circle is called a diameter.