Area of a pentagon

The problem

Write a program that prompts the user to enter the length from the center of a pentagon to a vertex and computes the area of the pentagon.

Breaking it down

public static void main(String[] args) {

    Scanner input = new Scanner(;
    System.out.print("Enter the side: ");
    double lengthOfSide = input.nextDouble();

    double area = calculateArea(lengthOfSide);

    System.out.printf("The area of the pentagon is %.2f", area);

private static double calculateArea(double s) {
    double area = (5 * s * s) / (4 * Math.tan(Math.PI / 5));
    return area;


Enter the side: 5.5
The area of the pentagon is 52.04