Law of Sines Calculator
Solve a triangle from two angles and one side (AAS or ASA). Pick which two angles and which side you know.
③ WHY IT WORKS
Why the Law of Sines works
Drop an altitude h from vertex C onto side c. From one small right triangle h = a\u00B7sin B, and from the other h = b\u00B7sin A \u2014 so a\u00B7sin B = b\u00B7sin A, which rearranges to a/sin A = b/sin B. Repeating the altitude trick from the other vertices extends the chain to all three ratios, and that shared value also equals 2R, the diameter of the triangle\u2019s circumcircle.