JavaScript: Find the area of a triangle where lengths of the three of its sides are 5, 6, 7

JavaScript Basic: Exercise-4 with Solution

Write a JavaScript function to find the area of a triangle where lengths of the three of its sides are 5, 6, 7.

Sample Solution:

HTML Code:

<!DOCTYPE html>
<meta charset=utf-8 />
<title>The area of a triangle</title>

JavaScript Code:

var side1 = 5; 
var side2 = 6; 
var side3 = 7; 
var s = (side1 + side2 + side3)/2;
var area =  Math.sqrt(s*((s-side1)*(s-side2)*(s-side3)));

Sample Output:


Calculate the area of a triangle of three given sides :
In geometry, Heron's formula named after Hero of Alexandria, gives the area of a triangle by requiring no arbitrary choice of side as base or vertex as origin, contrary to other formulas for the area of a triangle, such as half the base times the height or half the norm of a cross product of two sides.

Area of a triangle

The Math.sqrt() function is used to get the square root of a number. If the value of the number is negative, Math.sqrt() returns NaN.

ES6 Version:

const side1 = 5; 
const side2 = 6; 
const side3 = 7; 
const perimeter = (side1 + side2 + side3)/2;
const area =  Math.sqrt(perimeter*((perimeter-side1)*(perimeter-side2)*(perimeter-side3)));

Live Demo:

See the Pen JavaScript: Area of Triangle - basic-ex-4 by w3resource (@w3resource) on CodePen.

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JavaScript: Tips of the Day

Converts a string to title case


const toTitleCase = str =>
    .map(x => x.charAt(0).toUpperCase() + x.slice(1))
    .join(' ');
console.log(toTitleCase('some_database_field_name')); // 'Some Database Field Name'
console.log(toTitleCase('Some label that needs to be title-cased')); // 'Some Label That Needs To Be Title Cased'
console.log(toTitleCase('some-package-name')); // 'Some Package Name'
console.log(toTitleCase('some-mixed_string with spaces_underscores-and-hyphens')); // 'Some Mixed String With Spaces Underscores And Hyphens' 


"Some Database Field Name"
"Some Label That Needs To Be Title Cased"
"Some Package Name"
"Some Mixed String With Spaces Underscores And Hyphens"