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

C
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Java
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// C program to calculate the area of an equilateral triangle
#include <stdio.h>
#include <math.h>
// Used for sqrt() function

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

    printf("Enter the side of an equilateral triangle::\n");
    scanf("%f", &s);

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

    // Output
    printf("\nArea of the equilateral triangle = %f sq. units", a);
    return 0;
}