Given a n-sided regular polygon of side length a.The task is to find the length of it’s diagonal.
Examples:
Input: a = 9, n = 10 Output: 17.119 Input: a = 4, n = 5 Output: 6.47213
Approach:
We know that the sum of interior angles of a polygon = (n – 2) * 180 where, n is the no. of sides in the polygon.
So, each interior angle = (n – 2) * 180/n
Now, we have to find BC = 2 * x. If we draw a perpendicular AO on BC, we will see that the perpendicular bisects BC in BO and OC, as triangles AOB and AOC are congruent to each other.
Now, t = (n – 2) * 180/2n
So, sint = x/a
Therefore, x = asint
Hence, diagonal=2x = 2asint = 2asin((n – 2) * 180/2n)
C++
// C++ Program to find the diagonal // of a regular polygon with given side length #include <bits/stdc++.h> using namespace std; // Function to find the diagonal // of a regular polygon float polydiagonal( float n, float a) { // Side and side length cannot be negative if (a < 0 && n < 0) return -1; // diagonal // degree converted to radians return 2 * a * sin ((((n - 2) * 180) / (2 * n)) * 3.14159 / 180); } // Driver code int main() { float a = 9, n = 10; cout << polydiagonal(n, a) << endl; return 0; } |
Java
// Java Program to find the diagonal // of a regular polygon with given side length class GFG { // Function to find the diagonal // of a regular polygon static float polydiagonal( float n, float a) { // Side and side length cannot be negative if (a < 0 && n < 0 ) { return - 1 ; } // diagonal // degree converted to radians return ( float ) ( 2 * a * Math.sin((((n - 2 ) * 180 ) / ( 2 * n)) * 3.14159 / 180 )); } // Driver code public static void main(String[] args) { float a = 9 , n = 10 ; System.out.printf( "%.3f" ,polydiagonal(n, a)); } } // This code is contributed by 29AjayKumar |
Python3
# Python3 Program to find the diagonal # of a regular polygon with given side length import math as mt # Function to find the diagonal # of a regular polygon def polydiagonal(n, a): # Side and side length cannot # be negative if (a < 0 and n < 0 ): return - 1 # diagonal degree converted to radians return ( 2 * a * mt.sin((((n - 2 ) * 180 ) / ( 2 * n)) * 3.14159 / 180 )) # Driver code a, n = 9 , 10 print (polydiagonal(n, a)) # This code is contributed # by Mohit kumar 29 |
C#
// C# Program to find the diagonal // of a regular polygon with given side length using System; public class GFG{ // Function to find the diagonal // of a regular polygon static float polydiagonal( float n, float a) { // Side and side length cannot be negative if (a < 0 && n < 0) { return -1; } // diagonal // degree converted to radians return ( float ) (2 * a * Math.Sin((((n - 2) * 180) / (2 * n)) * 3.14159 / 180)); } // Driver code static public void Main (){ float a = 9, n = 10; Console.WriteLine(polydiagonal(n, a)); } } // This code is contributed by @Sachin... |
PHP
<?php // PHP Program to find the diagonal of a // regular polygon with given side length // Function to find the diagonal // of a regular polygon function polydiagonal ( $n , $a ) { // Side and side length cannot // be negative if ( $a < 0 && $n < 0) return -1; // diagonal // degree converted to radians return 2 * $a * sin(((( $n - 2) * 180) / (2 * $n )) * 3.14159 / 180); } // Driver code $a = 9; $n = 10; echo polydiagonal( $n , $a ); // This code is contributed // by Sach_Code ?> |
Javascript
<script> // javascript Program to find the diagonal // of a regular polygon with given side length // Function to find the diagonal // of a regular polygon function polydiagonal(n , a) { // Side and side length cannot be negative if (a < 0 && n < 0) { return -1; } // diagonal // degree converted to radians return (2 * a * Math.sin((((n - 2) * 180) / (2 * n)) * 3.14159 / 180)); } // Driver code var a = 9, n = 10; document.write(polydiagonal(n, a).toFixed(3)); // This code contributed by Princi Singh </script> |
17.119
Time Complexity: O(1)
Auxiliary Space: O(1)
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