Perimeter of Triangle Calculator

Calculate the perimeter of any triangle by entering the lengths of its three sides. This calculator also identifies the type of triangle based on the side lengths and validates that the measurements form a valid triangle.

How to Use This Calculator

1. Enter the length of the first side of the triangle
2. Enter the length of the second side of the triangle
3. Enter the length of the third side of the triangle
4. Click "Calculate Perimeter" to get the result
5. The calculator will display the perimeter and identify the triangle type

Understanding Triangle Perimeter

The perimeter of a triangle is the total distance around the triangle, calculated by adding the lengths of all three sides together. The formula is simple: P = a + b + c, where a, b, and c are the lengths of the three sides.

Triangle Types

This calculator also identifies the type of triangle based on side lengths:

• Equilateral Triangle: All three sides are equal in length
• Isosceles Triangle: Two sides are equal in length
• Scalene Triangle: All three sides have different lengths

Triangle Inequality Theorem

For three lengths to form a valid triangle, they must satisfy the triangle inequality theorem: the sum of any two sides must be greater than the third side. This calculator automatically validates this requirement and will alert you if the entered measurements cannot form a valid triangle.