Question

Program62

Write a class that has a main method and two more methods for performing calculations on a circle. One void method calculates and prints the circumference of the circle and the other method returns the area of the circle. The main method should prompt the user to enter the diameter of the circle (as a double) and call the other methods with this input as an argument. Both the circumference and area should be displayed accurate to three decimal places.
Sample Output (user input shown in blue)

Enter the diameter of the circle
12.25
The circumference is 38.485
The area is 117.859

Answer 1

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Java Program

import java.util.Scanner;
public class Circle
{
   public static void main(String[] args)
   {  
   Scanner sc = new Scanner(System.in);
   //Prompt the user to enter the diameter of the circle (as a double)
   System.out.print("Enter the diameter of the circle:");
        double diameter = sc.nextDouble();
      
   //void method print_circumference(radius) that calculates and prints the circumference of the circle
        print_circumference(diameter);
   //calculate_area(radius) method returns the area of the circle
        double area=calculate_area(diameter);
        System.out.printf("\nThe area is %.3f", area);
         }
   public static void print_circumference(double diameter)
   {
   double radius=diameter/2;
   //Circumference = 2*PI*radius
        double circumference= Math.PI * 2*radius;
        System.out.printf( "The circumference is %.3f",circumference) ;
   }
   public static double calculate_area(double diameter)
   {
   double radius=diameter/2;
   //Area = PI*radius*radius
        double area = Math.PI * (radius * radius);
   return(area);
   }
}

Output

Enter the diameter of the circle:12.25
The circumference is 38.485
The area is 117.859