public class Ring extends Kujund{
  protected int r;
  public Ring(int x, int y, int r){
    super(x, y);
    this.r=r;
  }
  public double pindala(){
    return Math.PI*r*r;
  }
  public void joonista(java.awt.Graphics g){
     g.drawOval(x-r, y-r, 2*r, 2*r);
  }
}