给定整数d ,它是五边形的对角线的长度,任务是找到该五边形的面积。
例子:
Input: d = 5
Output: 16.4291
Input: d = 10
Output: 65.7164
方法:五角大楼是一个规则的多边形,具有五个相等的边和所有相等的角度。五边形的内角各为108度,五边形的所有角之和为540度。如果d是五边形的对角线,则其面积由下式给出:
下面是上述方法的实现:
C++
// C++ program to find the area of
// Pentagon with given diagonal
#include
using namespace std;
// Function to return the area of the
// pentagon with diagonal d
float pentagonArea(float d)
{
float area;
// Formula to find area
area = (d * d * (-5 + sqrt(45)) * sqrt(sqrt(20) + 5)) / 8;
return area;
}
// Driver code
int main()
{
float d = 5;
cout << pentagonArea(d);
return 0;
}
Java
// Java program to find the area of
// Pentagon with given diagonal
import java.text.*;
class GFG{
// Function to return the area of the
// pentagon with diagonal d
static double pentagonArea(double d)
{
double area;
// Formula to find area
area = (d * d * (-5 + Math.sqrt(45)) * Math.sqrt(Math.sqrt(20) + 5)) / 8;
return area;
}
// Driver code
public static void main(String[] args)
{
double d = 5;
DecimalFormat dec = new DecimalFormat("#0.0000");
System.out.println(dec.format(pentagonArea(d)));
}
}
// This code is contributed by mits
Python3
# Python3 program to find the area of
# Pentagon with given diagonal
# from math lib import sqrt() method
from math import sqrt
# Function to return the area of the
# pentagon with diagonal d
def pentagonArea(d) :
# Formula to find area
area = (d * d * (-5 + sqrt(45)) * sqrt(sqrt(20) + 5)) / 8
return round(area , 4)
# Driver code
if __name__ == "__main__" :
d = 5
print(pentagonArea(d))
# This code is contributed by Ryuga
C#
// C# program to find the area of
// Pentagon with given diagonal
using System;
class GFG{
// Function to return the area of the
// pentagon with diagonal d
static double pentagonArea(double d)
{
double area;
// Formula to find area
area = (d * d * (-5 + Math.Sqrt(45)) * Math.Sqrt(Math.Sqrt(20) + 5)) / 8;
return area;
}
// Driver code
public static void Main()
{
double d = 5;
Console.WriteLine("{0:F4}",pentagonArea(d));
}
}
// This code is contributed by mits
PHP
Javascript
输出:
16.4291