PHP class for circle: Area and circumference calculation

PHP OOP: Exercise-2 with Solution

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 :

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


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: Area and circumference calculation.

PHP Code Editor:

Contribute your code and comments through Disqus.

Previous: Area and perimeter calculation.
Next: Abstract method and subclass implementation.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.

Follow us on Facebook and Twitter for latest update.