Law of Sines Calculator
Find Unknown Side (AAS/ASA)
Find side b given side a, angle A, and angle B
Find Unknown Angle (SSA)
Find angle B given sides a, b and angle A (ambiguous case)
Formula
a/sin(A) = b/sin(B) = c/sin(C) | sin(B) = b·sin(A)/a
Frequently Asked Questions
What is the Law of Sines?
The Law of Sines states: a/sin(A) = b/sin(B) = c/sin(C), where a, b, c are sides and A, B, C are opposite angles. It relates the ratio of each side to the sine of its opposite angle.
What is the ambiguous case (SSA)?
When given two sides and a non-included angle (SSA), there may be 0, 1, or 2 valid triangles. This occurs because sin(B) = sin(180°-B), creating two possible angles. You must check if both angles produce valid triangles (all angles positive and summing to 180°).
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