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Trigonometry Calculators

Law of Sines Calculator

Solve a triangle with the law of sines from two angles and a side (AAS/ASA): all sides, angles and the area.

Enter values

Results update as you type.

Result

Side b

13.472964

Side c
15.320889
Angle C
80 °
Area
66.341395
Step-by-stepShow
  1. a/sin A = 15.557238
  2. b = 15.557238 × sin 60° = 13.472964

About the Law of Sines Calculator

Solve a triangle with the law of sines from two angles and a side (AAS/ASA): all sides, angles and the area.

Also known as: sine rule, law of sines, aas triangle, asa triangle.

How to use this calculator

  1. Enter angle a, angle b, side a (opposite a).
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Open “Step-by-step” to see how the answer was worked out.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

a / sin A = b / sin B = c / sin C

Worked example

Using the values pre-filled in the calculator above:

  • Angle A = 40 °
  • Angle B = 60 °
  • Side a (opposite A) = 10

the calculator returns:

  • Side b: 13.472964
  • Side c: 15.320889
  • Angle C: 80 °
  • Area: 66.341395

Working

  1. a/sin A = 15.557238
  2. b = 15.557238 × sin 60° = 13.472964