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Classifying Triangles Calculator

Result

Calculated result Scalene / Right Based on the values entered.
↗ Math

Classifying Triangles Calculator — free online calculator.

Formula

Method: Validate the three sides, classify the side type as Equilateral/Isosceles/Scalene, then compare c² with a²+b² to classify the angle type as Acute/Right/Obtuse.
  • Classifying Triangles Calculator calculates its result from Side a, Side b, Side c. It uses the formula Calculated with the verified ST Calculator runtime.. Change any input to recalculate the result instantly.
  • The main inputs are Side a, Side b, Side c. Enter them in the units and format shown in the calculator.
  • Keep comparable quantities in compatible units whenever the formula combines or compares them.
  • Changing any input above recalculates the result with the same calculation engine used by this page.

Example: Classifying Triangles

Inputs
  • Side a: 3
  • Side b: 4
  • Side c: 5

Using Side a = 3, Side b = 4, Side c = 5, the calculated result is Scalene / Right.

Sample result: Calculating…

Frequently asked questions

What does the Classifying Triangles calculate?

Classifying Triangles Calculator — free online calculator.

Which values should I enter?

Enter Side a, Side b, Side c using the units and format shown beside each field.

What formula does this calculator use?

The calculator uses the following relationship: Method: Validate the three sides, classify the side type as Equilateral/Isosceles/Scalene, then compare c² with a²+b² to classify the angle type as Acute/Right/Obtuse..

Why might my result differ from another source?

Results can differ when another source uses different units, rounding rules, conventions or assumptions. Compare the inputs and definitions before comparing results.

Does the result update automatically?

Yes. Changing an input updates the result using the same calculation engine shown on this page.

Page information

Updated: October 7, 2026