Oblique Triangle Calculator
Solve any non-right triangle from three known parts.
Enter your values
ⓘ Live results
Results
- Side c
- 6.66634
- Angle A
- 46.237°
- Angle B
- 96.763°
- Angle C
- 37°
- Area
- 26.47986
- Perimeter
- 25.66634
- Circumradius
- 5.53853
- Inradius
- 2.06339
Quick answer
Non-right triangles are solved with the law of cosines (c² = a² + b² − 2ab·cos C) and the law of sines (a ÷ sin A = b ÷ sin B).
c² = a² + b² − 2ab·cos C
How to use the Oblique Triangle Calculator
- 1Choose whether you know two sides and the included angle, or all three sides.
- 2Enter sides a and b.
- 3Enter the included angle in degrees (SAS) or the third side (SSS).
Worked example
Using the values the calculator loads with:
Inputs
- What do you know?Two sides and the angle between (SAS)
- Side a8
- Side b11
- Angle C in degrees (SAS) or side c (SSS)37
Results
- Side c6.66634
- Angle A46.237°
- Angle B96.763°
- Angle C37°
- Area26.47986
- Perimeter25.66634
- Circumradius5.53853
- Inradius2.06339
Frequently asked questions
What is the ambiguous case?
SSA — two sides and a non-included angle can give two valid triangles. This tool uses SAS and SSS, which are always unique.
Can I use it for right triangles?
Yes. Set the included angle to 90° and the law of cosines collapses to Pythagoras.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.