Geometry Foundational

Triangle Inequality Theorem

Enter three side lengths to verify all three triangle inequality conditions. If valid, all three angles are computed via the Law of Cosines and a scaled diagram is drawn.

All 3 inequalities checked
Angles via Law of Cosines
Triangle or failure diagram
Inputs — Side Lengths
Result
Enter side lengths and click Check.
Step-by-Step Solution
Diagram
Put It Into Practice

The calculator shows the steps — a quiz proves you can do them on your own.

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