第六章第三十五题（几何：五边形的面积）(Geometry: area of a pentagon) - 编程练习题答案

6.35（几何：五边形的面积）五边形的面积可以使用下面的公式计算：

编写一个方法，使用下面的方法头来返回五边形的面积。

public static double area(double side)

编写一个主方法，提示用户输入五边形的边，然后显示它的面积。

下面是一个运行示例：

Enter the side:5.5

The area of the pentagon is 52.044441

6.35(Geometry: area of a pentagon)The area of a pentagon can be computed using the following formula:

Write a method that returns the area of a pentagon using the following header:

public static double area(double side)

Write a main method that prompts the user to enter the side of a pentagon and displays its area.

Here is a sample run:

Enter the side:5.5

The area of the pentagon is 52.044441

下面是参考答案代码:

// https://cn.fankuiba.com
import java.util.Scanner;

public class Ans6_35_page205 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Enter the side: ");
        double side = input.nextDouble();
        System.out.println("The area of the pentagon is "+area(side));
    }
    public static double area(double side) {
        return  (5 * side * side) / (4 * Math.tan(Math.PI / 5));
    }
}