Write a C program to check whether triangle is valid or not if angles are given using if else. How to check whether a triangle can be formed or not, if its angles are given using if else in C programming. Program to check a valid triangle based on its angles in C. Logic to check triangle validity if angles are given in C program.

**Example**

**Input**

Input first angle: 60 Input second angle: 30 Input third angle: 90

**Output**

The triangle is valid

## Required knowledge

Basic C programming, If else, Basic Mathematics

## Property of a triangle

A triangle is said to be a valid triangle if and only if sum of its angles is `180 °`

.

## Logic to check triangle validity if angles are given

Below is the step by step descriptive logic to check whether a triangle can be formed or not, if angles are given.

- Input all three angles of the triangle in some variable say angle1, angle2 and angle3.
- Find sum of all three angles, store it in some variable say sum = angle1 + angle2 + angle3.
- If sum == 180 then, the triangle can be formed otherwise not. Make sure angles are greater than 0.

## Program to check triangle validity when angles are given

```
/**
* C program to check whether a triangle is valid or not if angles are given
*/
#include <stdio.h>
int main()
{
int angle1, angle2, angle3, sum;
/* Input all three angles of triangle */
printf("Enter three angles of triangle: \n");
scanf("%d%d%d", &angle1, &angle2, &angle3);
/* Calculate sum of angles */
sum = angle1 + angle2 + angle3;
/* Check the triangle validity property */
if(sum == 180 && angle1!=0 && angle2!=0 && angle3!=0)
{
printf("Triangle is valid.");
}
else
{
printf("Triangle is not valid.");
}
return 0;
}
```

Output

Enter three angles of triangle: 30 60 90 Triangle is valid.

Happy coding 😉

<pre><code> ----Your Source Code---- </code></pre>