area of multiple traingle
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Enter r for right angled triangle\n" +
                "Enter e for equilateral triangle\n" +
                "Enter i for isosceles triangle\n" +
                "Enter s for scalene triangle: ");
        char typeOfTriangle = scanner.next().charAt(0);
        switch (typeOfTriangle) {
            case 'r' -> {
                System.out.print("Enter base length: ");
                float base = scanner.nextFloat();
                System.out.print("Enter perpendicular length: ");
                float perpendicular = scanner.nextFloat();
                float areaOfRightAngledTriangle = 0.5f * base * perpendicular;
                System.out.println("The area is: " + areaOfRightAngledTriangle);
            }
            case 'e' -> {
                System.out.print("Enter the equal length: ");
                float equalLength = scanner.nextFloat();
                double areaOfEquilateralTriangle = (Math.sqrt(3) / 4) * Math.pow(equalLength, 2);
                System.out.printf("The area is %.2f", areaOfEquilateralTriangle);
            }
            case 'i' -> {
                System.out.print("Enter length of same side: ");
                float equalLength = scanner.nextFloat();
                System.out.print("Enter length of the other side: ");
                float base = scanner.nextFloat();
                float height = (float) Math.sqrt(Math.pow(equalLength, 2) - (base / 4));
                double area = 0.5f * base * height;
                System.out.printf("The area is %.2f", area);
            }
            case 's' -> {
                System.out.print("Enter the sides (a,b,c): ");
                float side1 = scanner.nextFloat(), side2 = scanner.nextFloat(), side3 = scanner.nextFloat();
                float semiPerimeter = (side1 + side2 + side3) / 2;
                double area = Math.sqrt(semiPerimeter * (semiPerimeter - side1) * (semiPerimeter - side2) * (semiPerimeter - side3));
                System.out.printf("The area is %.2f", area);
            }
            default ->
                System.out.println("Invalid Choice");
        }
    }
}
