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

## Logic to check triangle validity if angles are given

As I mentioned it above solving this program requires basic mathematics. You must be aware of basic properties of triangle before attempting this program. Let us first learn basic properties of triangle.

### Property of a triangle

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

After knowing the basic property of triangle let us move on to the logic of this program. Below is the step by step descriptive logic to check whether a triangle can be formed or not, if angles are given.

- Read all three angles of the triangle in some variable say a, b and c.
- Find sum of all three angles, store the sum in some variable say sum = a + b + c.
- Check if sum == 180. If sum == 180, then make sure angles are greater than 0, then the triangle can be formed otherwise not.

## 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 a, b, c, sum; //a, b, c are three angles of a triangle /* Read all three angles of triangle */ printf("Enter three angles of triangle: \n"); scanf("%d%d%d", &a, &b, &c); /* Calculate sum of angles */ sum = a + b + c; /* Check the triangle validity property */ if(sum == 180 && a!=0 && b!=0 && c!=0) { printf("Triangle is valid."); } else { printf("Triangle is not valid."); } return 0; }

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

Happy coding ;)

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