Triangle Solver
Solve any triangle from SSS, SAS, ASA, AAS or SSA using the law of sines and cosines.
Mode: SSS — 3 Sides. Angles in degrees.
Triangle Diagram
Sides
a
3
b
4
c
5
Angles
A
36.869898°
B
53.130102°
C
90°
Area
6
Perimeter
12
TriangleTrigonometryLaw of SinesLaw of CosinesGeometry
Solve any triangle from any three known values (sides or angles) using the law of sines and law of cosines. Supports SSS, SAS, ASA, AAS and SSA cases.
Key Features
Five Modes
SSS, SAS, ASA, AAS and SSA — covers every combination of known sides and angles.
Law of Cosines
Used for SSS and SAS cases: c² = a² + b² − 2ab·cos(C).
Law of Sines
Used for ASA, AAS and SSA: a/sin(A) = b/sin(B) = c/sin(C).
Complete Output
Finds all three sides, all three angles, area (Heron's formula) and perimeter.
SVG Diagram
Draws a labeled triangle diagram scaled to the actual proportions.
SSA Ambiguous Case
Detects and warns about the SSA ambiguous case where two triangles may exist.
How to Use
- 1Select the mode matching your known values (e.g. SSS for three sides).
- 2Enter the known values — angles in degrees.
- 3All remaining sides, angles, area and perimeter are computed instantly.