Kleines Programm um Flächeninhalt und Umfang von Kreisen zu berrechnen

Kreise.java

package net.karatek.randomstuff.math;

public class Kreise {
    public static void main(String[] args) {
        // Aufgabe Wert Einheit
        System.out.println("Aufgabe " + args[0]);
        System.out.println();
        area(Double.valueOf(args[1]), args[2]);
        System.out.println();
        extent(Double.valueOf(args[1]), args[2]);
        System.out.println("\n");
    }

    public static void area(double r, String unit) {
        System.out.println("r = " + r + unit);
        double A = Math.PI * r * r;
        System.out.println("A = π * r * r");
        System.out.println("A = π * " + r + " * " + r);
        A = A * 100;
        A = Math.round(A);
        A = A / 100;
        System.out.println("A = " + A + unit);
    }

    public static void extent(double r, String unit) {
        System.out.println("r = " + r + unit);
        double u = 2 * Math.PI * r;
        System.out.println("u = 2 * π * r");
        System.out.println("u = 2 * π * " + r);
        u = u * 100;
        u = Math.round(u);
        u = u / 100;
        System.out.println("u = " + u + unit);
    }
}