**What is a Tetrahedron?**

Thanks mathematische-basteleien.de |

If you look at the word tetrahedron (tetrahedron means "with four planes"), you could call every pyramid with a triangle as the base a tetrahedron.

However the tetrahedron is the straight, regular triangle pyramid on this website.

**Surface :**

......... | The area of the base and the lateral faces form the surface O. There is O=4*A (triangle) = sqr(3)a². |

**Java version of the n-queens problem is given below:**

/** * To change this template, choose Tools | Templates * and open the template in the editor. */ package area; import java.util.Scanner; /** * * @author ACHCHUTHAN */ public class Tetrahedron { double s1, s2, s3; Tetrahedron() { Scanner input = new Scanner(System.in); System.out.println("Enter side 1 length : "); s1 = input.nextDouble(); System.out.println("Enter side 2 length : "); s2 = input.nextDouble(); System.out.println("Enter side 3 length : "); s3 = input.nextDouble(); } public double getSurfaceArea() { double s = (s1 + s2 + s3) / 2; double a = Math.sqrt(s * (s - s1) * (s - s2) * (s - s3)); return (double)(4 * a); } public static void main(String args[]) { Tetrahedron t = new Tetrahedron(); System.out.println("***SurfaceArea of Tetrahedron****" + t.getSurfaceArea()); } }

**Output of this program is given bellow :**

run:

Enter side 1 length :

3

Enter side 2 length :

4

Enter side 3 length :

5

***SurfaceArea of Tetrahedron****24.0

BUILD SUCCESSFUL (total time: 4 seconds)