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PHP Math - pi() Function

The PHP Math pi() function returns the value of 𝜋 to the available precision. It returns the value of 𝜋 as 3.1415926535898. Please note that, M_PI constant yields the identical results to pi() function.




No parameter is required.

Return Value

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


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

$x = 5; 
$area = pi()*$x*$x;

echo "Value of the pi() is: ".pi()."\n";
echo "Value of the M_PI is: ".M_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
Value of the M_PI is: 3.1415926535898
Area of the circle with radius 5 is: 78.539816339745

❮ PHP Math Functions