Ambiguous Triangle (SSA) Calculator

°
Enter angle a (opposite a) in °.
units
Enter side a in units.
units
Enter side b in units.
Math

Ambiguous Triangle (SSA): calculate results from explicit inputs, with a formula and worked example.

Formula

sin B = b sin A / a; test B and 180°−B with A+B<180°

Example Calculation

Example inputs
  • Angle A (opposite a): 30 °
  • Side a: 5 units
  • Side b: 8 units

A = 30°, a = 5 and b = 8 yield two valid triangles, with B ≈ 53.1301° or 126.8699°.

Method references

Frequently asked questions

How do I use this calculator?

Enter angle a (opposite a), side a, side b. The result updates automatically. Use Reset to restore the example values.

What method does it use?

sin B = b sin A / a; test B and 180°−B with A+B<180°. Euclidean geometry. Use one consistent length unit; areas and volumes use its square and cube. Degenerate shapes are rejected. Very thin shapes may lose floating-point precision. Reports all valid nondegenerate SSA solutions, including none. Near-tangent cases within 10⁻¹⁴ in sin B are treated as one solution.

Why might a rounded result differ?

The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.

Are my inputs saved online?

No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.

Check the assumptions and units before using this result. Read about calculation methods.