Use our free Classifying Triangles Calculator to quickly determine the type of any triangle. Input side lengths to classify as equilateral, isosceles, or scalene, and find out if it's a right, acute, or obtuse triangle. Ideal for geometry students and quick reference.
Formula:
This calculator classifies triangles based on their side lengths (a, b, c) into two categories:
- By Sides:
- Equilateral: a = b = c
- Isosceles: Exactly two sides are equal (e.g., a = b, b ≠ c)
- Scalene: All three sides are different (a ≠ b ≠ c ≠ a)
- By Angles (where c is the longest side):
- Right: c2 = a2 + b2 (one angle is 90°)
- Acute: c2 < a2 + b2 (all angles are less than 90°)
- Obtuse: c2 > a2 + b2 (one angle is greater than 90°)