Solve any triangle. Enter any three values (at least one must be a side) to calculate all angles, sides, area, perimeter, and more. Supports all triangle types.
Sides: a (opposite A), b (opposite B), c (opposite C)
Angles: A, B, C in degrees. Leave unknown fields blank.
| Property | Value |
|---|
Any triangle can be solved if at least three of its six measurements (3 sides, 3 angles) are known, with at least one being a side length.
Used for SSS and SAS triangles: c² = a² + b² − 2ab·cos(C). Rearranged: cos(C) = (a² + b² − c²) / 2ab
Used for ASA, AAS, SSA: a/sin(A) = b/sin(B) = c/sin(C)
Given base and height: A = ½bh
Given two sides and included angle: A = ½ab·sin(C)
Heron's formula (three sides): A = √(s(s−a)(s−b)(s−c)) where s = (a+b+c)/2
| By sides | By angles |
|---|---|
| Equilateral: all sides equal | Acute: all angles < 90° |
| Isosceles: two sides equal | Right: one angle = 90° |
| Scalene: all sides different | Obtuse: one angle > 90° |