Triangle Inequality Checker
Check whether three side lengths can form a valid triangle.
Formula
a+b>c, a+c>b, b+c>a
The triangle inequality theorem: each side must be less than the sum of the other two sides.
Examples
3-4-5 (valid)
1-2-10 (invalid)
5-5-5 (valid)
Frequently Asked Questions
What is the triangle inequality theorem?
The sum of any two sides must be greater than the third side: a+b>c, a+c>b, b+c>a.
What happens when two sides equal the third?
The triangle degenerates into a straight line (degenerate triangle).
About this Calculator
Check whether three side lengths can form a valid triangle. All calculations are performed in your browser for instant results. Formulas are mathematically exact using JavaScript's built-in Math functions.