AAA Triangle Calculator
Determine if three angles form a valid triangle and classify it as acute, right, or obtuse. Free online AAA triangle angle calculator with instant results.
About This Calculator
The AAA Triangle Calculator checks whether three given angles can form a valid triangle and classifies the triangle type. In Euclidean geometry, the sum of interior angles must equal exactly 180 deg.
Triangle types by angles: Acute (all angles < 90 deg), Right (one angle = 90 deg), Obtuse (one angle > 90 deg).
Frequently Asked Questions
What is an AAA triangle?
AAA refers to a triangle described by its three angles. Unlike side-side-side (SSS), AAA does not uniquely determine a triangle's size -- all triangles with the same three angles are similar (same shape, different sizes). The angles must sum to 180 deg for a valid triangle.
How do angles determine triangle type?
If all three angles are less than 90 deg, the triangle is acute. If one angle equals 90 deg (within tolerance), it is right. If one angle exceeds 90 deg, it is obtuse. The sum of all three angles must equal 180 deg for a valid Euclidean triangle.
Can AAA determine triangle congruence?
No, AAA (Angle-Angle-Angle) determines similarity, not congruence. Triangles with equal angles are similar -- they have the same shape but can be different sizes. For congruence, you need SSS, SAS, ASA, or AAS criteria.