import java.util.*;
public class MathProgram {

	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);

		String shape;
		double length;
		double width;
		double base;
		double radius;
		double height;

		System.out.println("Please choose a shape:\n 1. Square\n 2. Rectangle\n 3. Triangle\n 4. Circle");
		shape = input.nextLine();


		switch (shape) {

		case "Square":

			System.out.println("Please enter the length/width of your squre: ");
			length = input.nextDouble();

			System.out.println("The area of your square is " + squareArea(length));

		break;

		case "Rectangle":

			System.out.println("Please enter the length of your rectangle: ");
			length = input.nextDouble();

			System.out.println("Please enter the width of your rectangle: ");
			width = input.nextDouble();

			System.out.println("The area of your rectangle is " + rectangleArea(length, width));

		break;

		case "Triangle":

			System.out.println("Please enter the base of your triangle: ");
			base = input.nextDouble();

			System.out.println("Please enter the height of your triangle: ");
			height = input.nextDouble();

			System.out.println("The area of your triangle is " + triangleArea(base, height));

		break;

		case "Circle":

			System.out.println("Please enter the radius of your circle: ");
			radius = input.nextDouble();

			System.out.println("The area of your circle is " + circleArea(radius));

		break;


		}

	}

	public static double squareArea(double length) {
		double area;

		area = Math.pow(length, 2);

		return area;

	}

	public static double rectangleArea (double length, double width) {
		double area;

		area = length * width;

		return area;

	}

	public static double triangleArea(double height, double base) {
		double area;

		area = (height * base) / 2.0;

		return area;


	}

	public static double circleArea(double radius) {
		double area;

		area = (Math.PI * Math.pow(radius, 2));

		return area;

	}

}