Introduction

In this demo I have used NetBeans IDE 8.2 for debugging purpose. But you can use any java programming language compiler as per your availability..

import java.util.Scanner;
class AreaOfEquilateralTriangle 
{
   public static void main(String args[]) 
    {   
       
          Scanner s = new Scanner(System.in);
          System.out.println("Enter the side of the Equilateral Triangle:");
          double a= s.nextDouble();
          double  area=(Math.sqrt(3)/4)*(a*a);
          System.out.println("Area of Equilateral Triangle is: " + area);      
     }
}

Result