/*(Corner point coordinates) Suppose a pentagon is centered at (0, 0) with one point

at the 0 o’clock position, as shown in Figure 4.7c. Write a program that prompts

the user to enter the radius of the bounding circle of a pentagon and displays the

coordinates of the five corner points on the pentagon. Here is a sample run:

Enter the radius of the bounding circle: 100

The coordinates of five points on the pentagon are

(95.1057, 30.9017)

(0.000132679, 100)

(-95.1056, 30.9019)

(-58.7788, -80.9015)

(58.7782, -80.902)

*/

import java.util.Scanner;

public class Exercise_04_07 {

public static void main(String[] args) {

Scanner input = new Scanner(System.in);

System.out.print("Enter the radius of the bounding circle: ");

double radius = input.nextDouble();

// Starts with 18 degrees, 360 divided by 5 is 72 degrees according to sample

double angleP1 = Math.toRadians(18);

double angleP2 = Math.toRadians(18 + 72);

double angleP3 = Math.toRadians(18 + 72 * 2);

double angleP4 = Math.toRadians(18 + 72 * 3);

double angleP5 = Math.toRadians(18 + 72 * 4);

double x1 = radius * Math.cos(angleP1);

double y1 = radius * Math.sin(angleP1);

double x2 = radius * Math.cos(angleP2);

double y2 = radius * Math.sin(angleP2);

double x3 = radius * Math.cos(angleP3);

double y3 = radius * Math.sin(angleP3);

double x4 = radius * Math.cos(angleP4);

double y4 = radius * Math.sin(angleP4);

double x5 = radius * Math.cos(angleP5);

double y5 = radius * Math.sin(angleP5);

System.out.println("The coordinates of five points on the pentagon are ");

System.out.println("(" + x1 + "," + y1 + ")");

System.out.println("(" + x2 + "," + y2 + ")");

System.out.println("(" + x3 + "," + y3 + ")");

System.out.println("(" + x4 + "," + y4 + ")");

System.out.println("(" + x5 + "," + y5 + ")");

}

}