给定整数a为正十边形的边,任务是查找并打印其对角线的长度。
例子:
Input: a = 5
Output: 9.51
Input: a = 9
Output: 17.118
方法:我们知道多边形的内角总和= (n – 2)* 180 ,其中, n为否。多边形中的边数。
因此,十边形的内角之和= 8 * 180 = 1440 ,每个内角将为144 。
现在,我们必须找到BC = 2 * x 。如果在BC上绘制垂直AO ,我们将看到BO和OC中的垂直二等分BC ,因为三角形AOB和AOC彼此相等。
因此,在三角形AOB中, sin(72)= x / a即x = 0.951 * a
因此,对角线长度将为2 * x,即1.902 * a 。
下面是上述方法的实现:
C++
// C++ program to find the diagonal
// of a regular decagon
#include
using namespace std;
// Function to return the diagonal
// of a regular decagon
float decdiagonal(float a)
{
// Side cannot be negative
if (a < 0)
return -1;
// Length of the diagonal
float d = 1.902 * a;
return d;
}
// Driver code
int main()
{
float a = 9;
cout << decdiagonal(a) << endl;
return 0;
}
Java
// Java program to find the diagonal of a regular decdiagonal
import java.util.*;
import java.lang.*;
import java.io.*;
public class GFG {
// Function to return the diagonal of a regular decdiagonal
static double decdiagonal(double a)
{
//side cannot be negative
if(a<0)
return -1;
// length of the diagonal
double d=1.902*a;
return d;
}
// Driver code
public static void main(String[] args)
{
int a = 9;
System.out.println(decdiagonal(a));
}
}
Python3
# Python3 program to find the diagonal
# of a regular decagon
# Function to return the diagonal
# of a regular decagon
def decdiagonal(a) :
# Side cannot be negative
if (a < 0) :
return -1
# Length of the diagonal
d = 1.902 * a
return d
# Driver code
if __name__ == "__main__" :
a = 9
print(decdiagonal(a))
# This code is contributed by Ryuga
C#
// C# program to find the diagonal of a regular decdiagonal
using System;
public class GFG {
// Function to return the diagonal of a regular decdiagonal
static double decdiagonal(double a)
{
//side cannot be negative
if(a<0)
return -1;
// length of the diagonal
double d=1.902*a;
return d;
}
// Driver code
public static void Main()
{
int a = 9;
Console.WriteLine(decdiagonal(a));
}
}
// This code is contributed by anuj_67..
PHP
Javascript
输出:
17.118