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Triangle Solver

Solve any triangle from SSS, SAS, ASA, AAS, or SSA.

Side a
3.000
Side b
4.000
Side c
5.000
Angle A
36.87°
Angle B
53.13°
Angle C
90.00°

Area: 6.000 square units

Perimeter: 12.000

Solves any triangle given enough info: SSS uses Law of Cosines, SAS combines Law of Cosines + Sines, ASA/AAS use Law of Sines. SSA is the ambiguous case - sometimes two valid triangles exist.

About

Pick which 3 elements you know (sides and/or angles). The tool applies Law of Cosines or Law of Sines as appropriate, fills in the missing pieces, and reports area and perimeter.

How to use

  1. Pick what you know (SSS, SAS, etc.).
  2. Fill in the values.

FAQ

Why does SSA sometimes have two answers?+

The ambiguous case. With two sides and a non-included angle, there can be 0, 1, or 2 valid triangles depending on the geometry. The tool returns the obtuse-angle version.