public class Sirkel implements Figurer {
  private double radius;

  public Sirkel(double radius){
    this.radius = radius;
  }

  public double hentAreal(){
    return Math.PI * Math.pow(radius, 2); //radius*radius
  }
  public double hentOmkrets(){
    return 2 * Math.PI * radius;
  }

  public String toString(){
    return "Sirkel (radius: " + radius + ").";
  }

}