Write a C Program to input two angles of a triangle and find third angle of the triangle. How to find all angles of a triangle if two angles are given by user using C programming. C program to calculate the third angle of a triangle if two angles are given.

**Example**Input

Enter first angle: 60 Enter second angle: 80

**Output**

Third angle = 40

## Required knowledge

Fundamentals of C, Data types, Talking user input in C

## Properties of triangle

We know that sum of all angles of a triangle is 180°.

Hence, by applying basic mathematics we can easily derive a formula for finding the third angle. The formula for third angle is given by.

## Logic to find third angle of a triangle

Basic step by step descriptive logic to find third angle of a triangle -

- Input two angles of triangle from user and store it in some variable say a and b.
- Apply formula for finding the third angle. Triangle formula is given by c = 180 - (a + b).
- Print value of third angle i.e. print c.

## Program to find angles of a triangle

```
/**
* C program to find all angles of a triangle if two angles are given
*/
#include <stdio.h>
int main()
{
int a, b, c;
// Input two angles of the triangle
printf("Enter two angles of triangle: ");
scanf("%d%d", &a, &b);
// Calculate the third angle
c = 180 - (a + b);
// Print value of the third angle
printf("Third angle of the triangle = %d", c);
return 0;
}
```

Output

Enter two angles of triangle: 60 30 Third angle of the triangle = 90

Happy coding 😉

### Recommended posts

- Basic C programming exercise index.
- C program to find area of triangle.
- C program to find area of equilateral triangle.
- C program to check whether a triangle is valid or not if all angles are given.
- C program to check whether a triangle is valid or not if all sides are given.
- C program to check whether a triangle is Equilateral, Scalene or Isosceles triangle.
- C program to find area of rectangle.

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