JavaScript: Find the Area of a Circle

1. Introduction

Finding the area of geometric shapes is a fundamental concept in mathematics. For a circle, the area is calculated using the formula: area = π * radius^2. In this article, we'll be creating a JavaScript program to compute the area of a circle given its radius.

2. Program Overview

This guide will take you through:

1. Specifying the radius of the circle.

2. Constructing a function to determine the area of the circle based on its radius.

3. Displaying the computed area.

3. Code Program

let radius = 5;  // Radius of the circle
let area;  // Variable to hold the area of the circle

// Function to compute the area of a circle
function findArea(r) {
    return Math.PI * r * r;

area = findArea(radius);

console.log("The area of a circle with radius " + radius + " units is: " + area.toFixed(2) + " square units.");


The area of a circle with radius 5 units is: 78.54 square units.

4. Step By Step Explanation

1. Variable Initialization: We initiate by designating the radius for which we want to compute the area. We also declare an area variable to store the result.

2. Area Calculation Function: The findArea(r) function performs the area computation. It uses the constant Math.PI to obtain the value of π (Pi) and then apply the formula for the area of a circle.

3. Computing the Area: We invoke our findArea function, passing in the defined radius, and save the outcome in the area variable.

4. Displaying the Result: We use console.log to output the radius and its corresponding circle area. We apply the toFixed(2) method to format the area, ensuring it's displayed with two decimal places for precision.