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The PHP pi() function is used to return the value of PI.

Syntax

pi()

Parameters

No parameter is required.

Return Value

Returns the value of PI, i.e., 3.1415926535898

Example:

In the below example, pi() function is used to calculate the area of a circle.

<?php
  $x = 5; 
  $area = pi()*$x*$x;

  echo "Value of the PI is: ".pi()."\n";
  echo "Area of the circle with radius $x is: ".$area."\n";
?>

The output of the above code will be:

Value of the PI is: 3.1415926535898
Area of the circle with radius 5 is: 78.539816339745

❮ PHP Math Functions