- Write a C program to read three angles of a triangle and check whether a triangle is valid or not.

#### Required Knowledge

A triangle is a **valid triangle**, If and only If **the sum of all internal angles is equal to 180**. This is known as angle sum property of triangle. We will use this triangle property to check whether three given angles can form a valid triangle.

## C program to check whether a triangle is valid, given angles of triangle

/* * Given three angles of a triangle, Write a c program to * check whether it is a valid triangle or not */ #include <stdio.h> int main() { int angle1, angle2, angle3; /* * Take three angles of triangle as input * from user using scanf */ printf("Enter Three Angles of a Triangle\n"); scanf("%d %d %d", &angle1, &angle2, &angle3); /* *Sum of all three angles of any triangle is 180 degree */ if( angle1 + angle2 + angle3 == 180) { printf("It is a Valid Triangle\n"); } else { printf("It is an invalid Triangle"); } return 0; }

Output

Enter Three Angles of a Triangle 30 60 90 It is a Valid Triangle

Enter Three Angles of a Triangle 60 70 80 It is an invalid Triangle

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