Find the side opposite angle B, and the third angle C, from side a and angles A and B.
| Side b | – |
| Angle C (°) | – |
Use this calculator for ASA or AAS: you know two angles and a non-included side a opposite A. The law of sines is a / sin A = b / sin B. Side b opposite B is therefore a × sin B / sin A. Angle C is 180° − A − B and must stay positive (A + B < 180°).
This is not the ambiguous SSA case (two triangles); only one b is returned. Side a must be positive. Angles are in degrees. A cannot be 0° or 180° (sin A would be 0).
Side a: Side opposite angle A, positive.
Angle A (°): Angle opposite side a.
Angle B (°): Angle opposite the unknown side b.
Side b: Side opposite B.
Angle C (°): The remaining angle, 180° − A − B.
Related calculators