Law Of Sines Calculator
How do I find triangle sides from one side and two angles? Enter the values below to calculate the result.
Result for the values shown.
Calculations run in your browser.
What to enter
| Input | Meaning and units |
|---|---|
| Side a (length) | Enter side a in length; use the same basis as the other measurements. |
| A (degree) | Enter a in degree; use the same basis as the other measurements. |
| B (degree) | Enter b in degree; use the same basis as the other measurements. |
Understanding your result
Read b (length), c (length) in the units and model stated on this page. The formula C=180-A-B · b=a*sin(B*pi/180)/sin(A*pi/180) · c=a*sin(C*pi/180)/sin(A*pi/180) defines the relationship; measurement accuracy and model applicability are separate from numerical precision.
Common mistakes
- Mixing input units or changing the physical meaning of a variable without changing the model.
Check your calculation
- Use the worked example as a known reference case, then change one input at a time and check the direction and units of the response.
Calculation checks, sources and review limits
How do I find triangle sides from one side and two angles?
How do I find triangle sides from one side and two angles? Enter the values below to calculate the result.
Common uses
- How do I find triangle sides from one side and two angles
How it works
C=180-A-B; b=a*sin(B*pi/180)/sin(A*pi/180); c=a*sin(C*pi/180)/sin(A*pi/180)
Worked example
Enter Side a: 5 length; A: 30 degree; B: 90 degree. Results: b: 10 length; c: 8.660254037844386 length.