How to Calculate the Area of a Circle in Java

Java is used extensively in mathematics because of how easy it is to perform calculations across different platforms.

One of the most common calculations is to calculate the area of a circle.

In this post, we'll learn how to calculate the area of a circle in Java.

How to calculate the area of a circle

The formula to calculate the area of a circle is well-known, it is πr².

Meaning we just take the radius of the circle and multiply it by itself, and then multiply it by pi.

Thankfully, we can use pi in Java by using the Math.PI constant.

Let's first start off with the example code:

JAVA
double radius = 5;
double area = Math.PI * radius * radius;

System.out.println(area);

BASH
78.53981633974483

Now, we can turn this into a re-usable method that accepts a radius as the parameter:

JAVA
public static double calculateArea(double radius) {
    return Math.PI * radius * radius;
}

Now we can just call this method:

JAVA
double area = calculateArea(5);

System.out.println(area);

BASH
78.53981633974483

Either way, it is very easy to calculate the area of a circle, and this reusable method can be used in any Java program.

Conclusion

In this post, we learned how to calculate the area of a circle in Java.

Simply apply the formula πr² with your desired radius and you'll get the area of the circle.

Thanks for reading and happy coding!

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