In this problem, we are given an integer n denoting the length of the side of a regular hexagon. Our task is to Find length of Diagonal of Hexagon.
Problem Description: Here, we have the side of a regular hexagon. And we need to find the length of the diagonal of the hexagon.
Let’s take an example to understand the problem,
Input: a = 7
Output: 12.11
Solution Approach
To solve the problem and find the length of diagonal which is given by the mathematical formula,
Diagonal = 1.73 * a
Let’s derive the formula,
Here, we have a regular polygon of length a.

The angle between the diagonal and side is 600.
The ratio of (d/2)/a is equal to sin 60o
Sin 60o = d/ 2*a
0.866 = d/ 2*a
d = 0.866 * 2 * a
d = 1.73 * a
Program to illustrate the working of our solution,
Example
#include <iostream>
using namespace std;
int main() {
float a = 12;
float d = 1.73 * a;
cout<<"The length of diagonal is "<<d;
return 0;
}Output
The length of diagonal is 20.76