# What is a radius of a circle?

A circle is a collection of points on a two-dimensional plane, which are equidistant from the center point 'O'.

## Answer: The distance from the center point to any endpoint on the circle is called the radius of a circle.

**Let us know about the radius of a circle in detail.**

**Explanation:**

The radius of a circle is the length of the line segment from the center of a circle to a point on the circumference of the circle. It is generally abbreviated as ‘r’.

The radius of a circle can be calculated through various formulas. Observe the following formulas to calculate the radius:

- When the diameter is known, the formula for the radius of a circle is: Radius = Diameter / 2
- When the circumference is known, the formula for the radius is: Radius = Circumference / 2π
- When the area is known, the formula for the radius is: Radius = ⎷(Area of the circle / π)