Php Code for Annulus Area

This php programming code is used to find the annulus area . You can select the whole php code by clicking the select option and can use it. When you click text, the code will be changed to text format. This php program code will be opened in a new pop up window once you click pop-up from the right corner. You can just copy, paste this php code and use it to find the annulus area .

<?php 
$radiusOuter=21;
$radiusInner=10;
    if($radiusInner>$radiusOuter)
    {
        echo "\nOuter Radius should be greated than Inner Radius";
    }
    else
    {
        $area=3.14*(pow($radiusOuter,2)-pow($radiusInner,2));
        echo "\nArea of Annulus = ".$area;
    }
?>