JavaScript/Basic Programs/Program

Area and Perimeter of Rectangle

Program to calculate area and perimeter of a rectangle

JavaScriptBeginner
JavaScript
Try
// Formula: Area = length × width
// Formula: Perimeter = 2 × (length + width)

let length = 10;
let width = 5;

let area = length * width;
let perimeter = 2 * (length + width);

console.log("Rectangle Dimensions:");
console.log("Length:", length);
console.log("Width:", width);
console.log("Area:", area, "square units");
console.log("Perimeter:", perimeter, "units");

// Function version
function rectangleArea(length, width) {
    return length * width;
}

function rectanglePerimeter(length, width) {
    return 2 * (length + width);
}

let rectLength = 8;
let rectWidth = 6;

console.log("\nUsing functions:");
console.log(`Area: ${rectangleArea(rectLength, rectWidth)} sq units`);
console.log(`Perimeter: ${rectanglePerimeter(rectLength, rectWidth)} units`);

Output

Rectangle Dimensions:
Length: 10
Width: 5
Area: 50 square units
Perimeter: 30 units

Using functions:
Area: 48 sq units
Perimeter: 28 units

This program calculates the area and perimeter of a rectangle using geometric formulas.

Rectangle Formulas

  1. Area: length × width

    • Measured in square units
    • Represents the space inside the rectangle

  2. Perimeter: 2 × (length + width)

    • Measured in linear units
    • Represents the total distance around the rectangle

Example Calculation

For a rectangle with length = 10 and width = 5:

  • Area = 10 × 5 = 50 square units
  • Perimeter = 2 × (10 + 5) = 2 × 15 = 30 units

Function Approach

Creating separate functions for each calculation:

javascript
function rectangleArea(length, width) {
    return length * width;
}

function rectanglePerimeter(length, width) {
    return 2 * (length + width);
}

Benefits:

  • Reusable functions
  • Clear separation of concerns
  • Easy to test
  • Can be used independently

Related Shapes

Square (special rectangle where length = width):

javascript
function squareArea(side) {
    return side * side; // or side ** 2
}

function squarePerimeter(side) {
    return 4 * side;
}

Real-world Applications

  • Flooring calculations
  • Fencing requirements
  • Painting area calculations
  • Land area measurements
  • Construction planning

Input Validation

Always validate inputs:

javascript
function rectangleArea(length, width) {
    if (length <= 0 || width <= 0) {
        return "Invalid dimensions";
    }
    return length * width;
}
Previous
Calculate Simple Interest