Areas

import java.text.DecimalFormat;
import java.util.Scanner;

public class Areas {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        DecimalFormat df = new DecimalFormat("#.###");
        String type = scanner.nextLine();
        if (type.equals("square")){
            double side = Double.parseDouble(scanner.nextLine());
            double area = side * side;
            System.out.printf(df.format(area));

        }else if (type.equals("rectangle")){
            double sideA = Double.parseDouble(scanner.nextLine());
            double sideB = Double.parseDouble(scanner.nextLine());
            double area = (sideA * sideB);
            System.out.printf(df.format(area));
        }else if (type.equals("circle")){
            double radius = Double.parseDouble(scanner.nextLine());
            double area = Math.PI * radius * radius;
            System.out.printf(df.format(area));
        }else if (type.equals("triangle")){
            double sideB = Double.parseDouble(scanner.nextLine());
            double h = Double.parseDouble(scanner.nextLine());
            double area = (sideB * h) / 2;

            System.out.printf("%.3f",area);

        }
    }
}