Solve any triangle with the solver tool
Use the Triangle solver in the Reference library when you know three parts of a triangle and want the rest, drawn to scale.
The Triangle solver works out every side, angle, the area and the perimeter from any three values (with at least one side). It handles SSS, SAS, ASA, AAS and the tricky SSA case, and draws the triangle to scale.
When two different triangles fit the same numbers (the ambiguous case), it shows both so you can compare them.
- Open the Reference library from the app, choose the Toolkits tab and tap Triangle solver.
- Fill in exactly three values. Side a is opposite angle A, side b is opposite angle B and side c is opposite angle C. Use the example buttons to load a sample.
- Read the full set of sides and angles, plus the area, perimeter and the law used for each step.
- In the ambiguous case, switch between Triangle 1 and Triangle 2 to see both solutions.
- Angles are in degrees by default. Change the angle unit to radians if your problem uses radians.
Tips
- If you get an error that angles add up to too much, check that angles are in the unit you think they are.
- Use the toolkit to check your own work from the law of sines and law of cosines guides.
Related guides
- Use the law of sinesFind a side of any triangle when you know the opposite angle of another side and its length.
- Use the law of cosinesFind the third side of a triangle when you know two sides and the angle between them.
- Browse the reference libraryFind shapes, formula cards, toolkits and labs, all in one searchable library.