Input
Enter side of the equilateral triangle: 10
Output
Area of equilateral triangle = 43.3 sq. units
Area of an equilateral triangle is given by formula: area = (sqrt(3) / 4) * (side * side)
#include <stdio.h>
#include <math.h>
int main()
{
float side, area;
printf("Enter side of an equilateral triangle: ");
scanf("%f", &side);
area = (sqrt(3) / 4) * (side * side);
printf("Area of equilateral triangle = %.2f sq. units", area);
return 0;
}