Find Circumference of a Circle using JavaScript

The Circumference of the Circle is: 2*pi*r. We can calculate this value in JavaScript using various approaches that are implemented below with examples and output.

These are the following approaches:

Using Arithmetic Operations

In this approach, we are using the formula for the circumference of a circle, which is given by 2πr, where r is the radius. By assigning the radius r=2 and performing the arithmetic operations, we calculate the circumference and display the result with three decimal places using toFixed(3).

Syntax:

let res = 2 * 3.1416 * r;

Example: The below example uses Arithmetic Operations to find the Circumference of a Circle in JavaScript.

Javascript

let r = 2;
let res = 2 * 3.1416 * r;
console.log(`${res.toFixed(3)}`);

Output

12.566

Using Math.PI

In this approach, we use the Math.PI property, representing the mathematical constant pi (approximately 3.141592653589793). By assigning the radius r=2 and using the formula 2×Math.PI×r, the program calculates the circumference of the circle and prints the result with three decimal places using toFixed(3).

Example: The below example uses Math.PI to find the Circumference of a Circle in JavaScript.

Javascript

const r = 2;
const res = 2 * Math.PI * r;
console.log(`${res.toFixed(3)}`);

Output

12.566

Using Math.PI and Math.pow

In this approach, the program uses the Math.PI property for the constant pi and the Math.pow method to calculate the square of the radius. By assigning the radius r=2 and using the formula π×r² the program calculates the area of the circle and displays the result with three decimal places using toFixed(3).

Example: The below example uses Using Math.PI and Math.pow to find the Circumference of a Circle in JavaScript.

Javascript

const r = 2;
const res = Math.PI * Math.pow(r, 2);
console.log(`${res.toFixed(3)}`);

Output

12.566