110 圖形面積

import java.util.Scanner;
public class JPA110 {

    public static void main(String args[]) {
   
        double totalarea;
        System.out.printf("圓形面積為：%f \n",calCircle(5));
        System.out.printf("三角形面積為：%f \n",calTriangle(10,5));
        System.out.printf("方形面積為：%f \n",calRectangle(5,10));
        totalarea = calCircle(5)+calTriangle(10,5)+calRectangle(5,10);
        System.out.printf("此圖形面積為：%f \n",totalarea);
    }
    static double calCircle(double r) {
        return r*r*Math.PI;
    }
   
    static double calTriangle(double x,double y) {
        return x*y;
    }
   
    static double calRectangle(double x,double y) {
        return x*y/2;
    }
}