In this tutorial I am going to show , how to find area of a circle using PHP , In this tutorial we learn how to use PHP Constant.
Formula for Calculation Area of circle :
A=πr² , where A=area, π(Pie)=3.14 and r=radius
Script / Code to to calculate area of a circle
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>PHP Find Area of a Circle Using Constant</title> </head> <body> <?php if(isset($_POST['submit'])){ //area = pie * radius * radius define('PI','3.14'); $radius=$_POST['radius']; $area= PI * $radius * $radius; echo "Area of the Circle is ".$area; } ?> <h2>Area of a Triangle</h2> <form action="" method="post"> <b>Enter Radius</b><br/> <input type="text" name="radius" ><br/> <input type="submit" name="submit" value="Submit"> </form> </body> </html>