Here’s a detailed explanation of the pi() function in PHP with an example and output.

What is pi()?

The pi() function in PHP returns the value of the mathematical constant π (pi), which is approximately 3.1415926535898.

Syntax:

pi()

Example with Output:

<?php
echo pi(); // Outputs: 3.1415926535898

Output:

3.1415926535898

Example with a Practical Use Case:

Let’s calculate the circumference and area of a circle using pi().

Example Code:

<?php
$radius = 7;

// Calculate circumference
$circumference = 2 * pi() * $radius;
echo "Circumference of the circle: " . $circumference . "\n";

// Calculate area
$area = pi() * pow($radius, 2);
echo "Area of the circle: " . $area;
?>

Output:

Circumference of the circle: 43.982297150257
Area of the circle: 153.9380400259

In this example:

• The circumference of the circle is calculated using the formula $2 \pi r$.
• The area is calculated using the formula $\pi r^2$, where r is the radius.

The pi() function is essential for performing any mathematical operations involving circles in PHP.