can you please solve 3 questions about the code

3) Consider the following class and answer the questions that follow:

public class Circle {

public static final double PI = 3.14159;

private double radius;

private double area;

public Circle(double r) {

radius=r;

}

public void calculateArea() { }

public String toString() { }

}

3.1 Complete the body of the method calculateArea() to calculate the area of the

circle.

3.2 Complete the body of the method toString() to return a string representation of the circle in this format:

Radius=the radius rounded to 2 decimal places

Area=the area rounded to 2 decimal places

3.3 Following the toString() method, add an accessor and mutator for the instance variable radius.