Example: C++ program to calculate the area of an equilateral triangle

C
C++
C#
Java
Python
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// C++ program to calculate the area of an equilateral triangle
#include <iostream>
#include <cmath>
// Used for sqrt() function
using namespace std;

int main() {
    float s, a;
    // s = side
    // a = area

    cout << "Enter the side of an equilateral triangle::\n";
    cin >> s;

    // Calculate area of equilateral triangle
    a = (sqrt(3) / 4) * (s * s);

    // Output
    cout << "\nArea of the equilateral triangle = " << a << " sq. units";
    return 0;
}