# Find Square Root in Javascript

In this example, you will learn to write a program to find square root in javascript.

But before going into the example, you must have knowledge of the following JavaScript topics:

Javascript Variables and Constants
Javascript Math.sqrt() Method

To find the square root of a number in javascript, we can use the `Math.sqrt()` method of javascript. Its syntax is:

``Math.sqrt(number);``

Here, `Math.sqrt()` takes in the number and returns its square root.

### Example 1: Find the Square Root of a Number

``````let num = 4;

// finding the square root
let root = Math.sqrt(num);
console.log(`Square root of \${num} is: \${root}`);``````

Output

Square root of 4 is: 2

### Example 2: Find the Square Root of the User Input Number

``````// user input number
let num = prompt('Enter the number: ');

// finding square root
let root = Math.sqrt(num);
console.log(`Square root of \${num} is: \${root}`);``````

Output

Enter the number: 4
Square root of 4 is: 2

### Example 3: Square Root of Different Data Types

``````let num1 = 4.8;
let num2 = 'Hello';
let num3 = '-4';

// finding square root
let root1 = Math.sqrt(num1);
let root2 = Math.sqrt(num2);
let root3 = Math.sqrt(num3);

console.log(`Square root of \${num1} is: \${root1}`);
console.log(`Square root of \${num2} is: \${root2}`);
console.log(`Square root of \${num3} is: \${root3}`);``````

Output

Square root of 4.8 is: 2.1908902300206643
Square root of Hello is: NaN
Square root of -4 is: NaN

If 0 or a positive value is passed, `Math.sqrt()` method will return the square root of that value

If a string is passed, `NaN` is returned

If a negative value is passed, `NaN` is returned.