Use the Law of Sines to find missing sides or angles in any triangle. Perfect for trigonometry problems.
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Enter Your Measurements
Results
Angle B (opposite to B)
48.59
degrees
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Formula
a/sin(A) = b/sin(B); sin(B) = (b × sin(A)) / a
How to Use This Calculator
How to Use
- 1
Enter side A and its opposite angle A.
- 2
Enter side B.
- 3
Click calculate to find angle B.
Frequently Asked Questions
Frequently Asked Questions
When do I use the Law of Sines?
Use it when you know a side and its opposite angle, plus another side or angle. It works for any triangle, not just right triangles.
What is the Law of Sines?
It states that a/sin(A) = b/sin(B) = c/sin(C) for any triangle, where lowercase letters are sides and uppercase are opposite angles.
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About This Calculator
This calculator uses the formula: a/sin(A) = b/sin(B); sin(B) = (b × sin(A)) / a. All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.
Built and maintained by the CalcSmart team. Last updated March 2026.
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