Здравейте ! Някой може ли да ми  помогне с решението на задачата. 

import java.util.Scanner;

public class Tasc9 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String figureType = scanner.nextLine();
        double area = 0;

        switch (figureType){
            case "square": {
                double a = Double.parseDouble(scanner.nextLine());
                area = a * a;
                break;
            }
            case "rectangle":{
                double a = Double.parseDouble(scanner.nextLine());
                double b = Double.parseDouble(scanner.nextLine());
                area = a * b;
                break;
            }
            case "circle": {
                double a = Double.parseDouble(scanner.nextLine());
                area = (a * a) * Math.PI;
                break;
            }
            case "triangle": {
                double a = Double.parseDouble(scanner.nextLine());
                double b = Double.parseDouble(scanner.nextLine());
                area = a * b;
                break;
            }

        }
    }
}