Chapter 4 Exercise 6, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

*4.6 (Random points on a circle) Write a program that generates three random points on a circle centered at (0, 0) with radius 40 and display three angles in a triangle formed by these three points, as shown in Figure 4.7a. (Hint: Generate a random angle a in radians between 0 and 2p, as shown in Figure 4.7b and the point determined by this angle is (r*cos(a), r*sin(a)).)

public class Exercise04_06 {
  public static void main(String args[]) {
    double r = 40;
   
    System.out.println("Three random points are ");
    
    double angle = Math.random() * 360;
    double x = r * Math.cos(angle * Math.PI / 180);
    double y = r * Math.sin(angle * Math.PI / 180);
    System.out.println("(" + x + ", " + y + ")");

    angle = Math.random() * 360;
    x = r * Math.cos(angle * Math.PI / 180);
    y = r * Math.sin(angle * Math.PI / 180);
    System.out.println("(" + x + ", " + y + ")");

    angle = Math.random() * 360;
    x = r * Math.cos(angle * Math.PI / 180);
    y = r * Math.sin(angle * Math.PI / 180);
    System.out.println("(" + x + ", " + y + ")");
  }
}