General Triangle Calculator for SSS, SAS, ASA, AAS and SSA

Updated By Unit Conversion Plus

Solve non-right and right triangles from the measurements you know, including the ambiguous SSA case.

Known measurements

How to solve a triangle

A triangle is determined by three suitable measurements, including at least one side. SSS and SAS use the cosine rule; ASA and AAS use the angle sum and sine rule. SSA may describe no triangle, one triangle or two different triangles.

Triangle formulas

a² = b² + c² − 2bc cos A · a/sin A = b/sin B = c/sin C · A + B + C = 180°

Results

Each solution includes all three sides and angles, perimeter, semiperimeter, area, circumradius and inradius.

Frequently asked questions

Why can SSA have two answers?

A known side can meet another side at two positions while preserving the given non-included angle.

Do three angles determine a triangle?

They determine its shape but not its size, so at least one side is required.