Java Program To Test Circle Dimensions To Prove Pie

So in trying to create a circle class, and use the dimensions of that circle (radius, area, etc.) to prove it will equal pie and print (3.141592653589793). This is my code so far it and am getting an error in the last two classes. I know it has to do with Circle(Radius); in the 2nd class but whenever i call upon it, it is assigned to itself. And in the last class im not too sure how to put the B= new b(1,1).

[public class Circle {
private double radius;
public Circle() {
radius = 0;
}
public Circle(double radius) {
this.radius = radius;

[Code] .....