How to Calculate Area of Equilatral Triangle using C Language

#include<stdio.h>
#include<math.h>
 
int main() {
   int side;
   float area, r_4;
 
   r_4 = sqrt(3) / 4;
 
   printf("\nEnter the Length of Side : ");
   scanf("%d", &side);
 
   area = r_4 * side * side;
 
   printf("\nArea of Equilateral Triangle : %f", area);
   return (0);
}

Output :

Enter the Length of Side : 5
Area of Equilateral Triangle : 10.82

Properties of Equilateral Triangle :

Equilateral triangle is a triangle in which all three sides are equal .
All angles are of measure 60 degree
A three-sided regular polygon

Formula to Calculate Area of Equilateral Triangle :

Explanation of Program :

First of all we have to find the value of Root 3 / 2. So we have used following statement to compute the value.

r_4 = sqrt(3) / 4 ;

Now after computing the value of the Root 3 by 2 we have multiplied it by Square of the side.

area = r_4 * side * side ;