JavaScript Program to Calculate Area and Circumference of a Circle

In this example, you will learn how to calculate the area and circumference of a circle using a simple JavaScript program.

// Circle radius
let radius = 5;

// Calc the Area
let area = Math.PI*radius*radius;

// Calc the circumference
let circumference = 2*Math.PI*radius;

// Print the area
console.log('The area of circle is: ' + area);

// Print the circumference
console.log('The circumference of circle is: '+ circumference);

Output:

The area of circle is: 78.53981633974483
The circumference of circle is: 31.41592653589793

Example 2:

In the above example, we imported the value of pi(π) from the Math library of JavaScript. You could also set its value manually and calculate the area and circumference of the circle.

However, this approach will give you the approximate value of the area and circumference, not the exact value:

// Circle radius
let radius = 5;

// Set PI(π) Value
const PI = 3.14

// Calc the Area
let area = PI*radius*radius;

// Calc the circumference
let circumference = 2*PI*radius;

// Print the area
console.log('The area of circle is: ' + area);

// Print the circumference
console.log('The circumference of circle is: '+ circumference);

Output:

The area of circle is: 78.5
The circumference of circle is: 31.400000000000002