### C program to find the third angle of a triangle :

In this tutorial, we will learn how to find the *third* angle of a triangle if the *first* and *second* angle is given.
We know that the sum of all three angles of a triangle is *180* degree. So, to find the third angle, we will *subtract* the sum of two angles from *180*. Letâ€™s take a look at the program :

### C Program code :

```
#include <stdio.h>
#define SUM 180
int main()
{
//1
float firstAngle, secondAngle, thirdAngle;
//2
printf("Enter first and second angle of the triangle : ");
scanf("%f %f", &firstAngle, &secondAngle);
//3
thirdAngle = SUM - (firstAngle + secondAngle);
//4
printf("You have entered %f and %f\n", firstAngle, secondAngle);
printf("Third Angle is : %f \n", thirdAngle);
}
```

### Explanation :

*The commented numbers above indicate the steps number below :*

- First, create three float variables to store all
*three angles*. - Ask the user to enter the
*first*and*second*angle of the triangle. And store it in variables*firstAngle*and*secondAngle*. - Now, calculate the third angle and store the value in variable
*thirdAngle*. - Print all angles:
*firstAngle,secondAngle and thirdAngle*

### Sample Outputs :

```
Enter first and second angle of the triangle : 120 30
You have entered 120.000000 and 30.000000
Third Angle is : 30.000000
Enter first and second angle of the triangle : 20
30
You have entered 20.000000 and 30.000000
Third Angle is : 130.000000
Enter first and second angle of the triangle : 13.5
12.5
You have entered 13.500000 and 12.500000
Third Angle is : 154.000000
```