PHP class for circle: Area and circumference calculation

Last update on May 29 2025 13:08:03 (UTC/GMT +8 hours)

2. Circle Class

Write a PHP class called 'Circle' that has a radius property. Implement methods to calculate the circle's area and circumference.

Sample Solution:

PHP Code :

<?php
class Circle {
    private $radius;

    public function __construct($radius) {
        $this->radius = $radius;
    }

    public function getArea() {
        return pi() * pow($this->radius, 2);
    }

    public function getCircumference() {
        return 2 * pi() * $this->radius;
    }
}

$circle = new Circle(7);
echo "Area: " . $circle->getArea() . "</br>";
echo "Circumference: " . $circle->getCircumference() . "</br>";
?>

Sample Output:

Area: 153.9380400259
Circumference: 43.982297150257

Explanation:

In the above exercise -

The "Circle" class has one private property: $radius, which represents the circle radius.
The constructor method __construct() initializes the circle radius.
The getArea() method calculates and returns the area of the circle using the formula: π * r^2, where π is a constant value obtained from the pi() function, and r is the radius of the circle.
The getCircumference() method calculates and returns the circle circumference using the formula: 2*π*r.

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP class that calculates a circle's diameter, area, and circumference and validates the radius input.
Write a PHP program that compares two Circle objects and outputs the one with the larger circumference.
Write a PHP script that implements a method to scale the circle by a certain factor and recalculate its measurements.
Write a PHP class that overrides the __toString() method to return a formatted string of the circle's properties.

Go to:

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PHP Code Editor:

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