# How to Determine if three lengths form a Triangle

We check if a triangle is valid or not using using Sides . Any triangle is valid if the sum of the two sides of a triangle is greater than the third side. We write java program using this approach .

## How to determine if three lengths form a triangle

Let’s A , B ,C are three sides of triangle then it form a triangle if

1. A+B > C
2. B+C > A
3. C+A > B

We write java program to check if a triangle is valid or not when sides are given .Now we will determine if three lengths form a triangle using java program .

``````import java.util.Scanner;

public class TriangleValid {
public static void main(String[] args) {

int side1 , side2, side3;
//create scanner object to get input from user
Scanner sc=new Scanner(System.in);

System.out.println("Enter side1 ");

//take input from user
side1 = sc.nextInt();

System.out.println("Enter side2 ");

//take input from user
side2 = sc.nextInt();

System.out.println("Enter side3 ");

//take input from user
side3 = sc.nextInt();

if( (side1 + side2 > side3) && (side2 + side3 > side1) && (side1 + side3 > side2) ){
System.out.println("This is valid triangle");
}else {
System.out.println("This is not valid triangle");
}

}
}``````

Output:

``````Enter side1
10
Enter side2
5
Enter side3
7
This is valid triangle``````

In this tutorial we learned how to determine if three lengths form a triangle using java .You can learn more java program for practice .