Java 5.36

问题及代码：

输入 number 和side 输出面积。

import java.util.Scanner;public class MyTriangle {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubSystem.out.println("please enter the number of sides and the side of a regular polygon: ");Scanner input = new Scanner(System.in);int number = input.nextInt();int side = input.nextInt();double are = area(number, side);System.out.println("the  area is " + are);}public static double area(int n, double side) {double area = (n * side * side) / (4 * Math.tan(3.1415926535 / n));return area;}}

运行结果：