# C Exercises: Check whether a triangle is Equilateral, Isosceles or Scalene

## C Conditional Statement: Exercise-14 with Solution

Write a C program to check whether a triangle is Equilateral, Isosceles or Scalene.

Equilateral triangle: An equilateral triangle is a triangle in which all three sides are equal. In the familiar Euclidean geometry, equilateral triangles are also equiangular; that is, all three internal angles are also congruent to each other and are each 60°.

Isosceles triangle: An isosceles triangle is a triangle that has two sides of equal length.

Scalene triangle: A scalene triangle is a triangle that has three unequal sides, such as those illustrated above.

**Pictorial Presentation:**

**Sample Solution**:

**C Code:**

```
#include <stdio.h>
int main()
{
int sidea, sideb, sidec; //are three sides of a triangle
/*
* Reads all sides of a triangle
*/
printf("Input three sides of triangle: ");
scanf("%d %d %d", &sidea, &sideb, &sidec);
if(sidea==sideb && sideb==sidec) //check whether all sides are equal
{
printf("This is an equilateral triangle.\n");
}
else if(sidea==sideb || sidea==sidec || sideb==sidec) //check whether two sides are equal
{
printf("This is an isosceles triangle.\n");
}
else //check whether no sides are equal
{
printf("This is a scalene triangle.\n");
}
return 0;
}
```

Sample Output:

Input three sides of triangle: 50 50 60 This is an isosceles triangle.

**Flowchart: **

**C Programming Code Editor:**

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