Law of Sines Calculator

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Understanding the Law of Sines

The Law of Sines Formula

a/sin(A) = b/sin(B) = c/sin(C) = 2R

where R is the radius of the circumscribed circle

This law relates the lengths of the sides of a triangle to the sines of the corresponding angles.

When to Use the Law of Sines

ASA Case

Known: Two angles and one side

Find: Remaining side and angle

AAS Case

Known: Two angles and non-included side

Find: Remaining side and angle

SSA Case

Known: Two sides and non-included angle

Find: Remaining angles (may have two solutions)

The Ambiguous Case (SSA)

When using two sides and a non-included angle (SSA), there may be:

  • No solution (impossible triangle)
  • One solution (right triangle)
  • Two solutions (ambiguous case)

This occurs because the same inputs could describe two different triangles.

Applications

Surveying

Used to find distances and heights of inaccessible points

Navigation

Essential in maritime and aerial navigation

Physics

Used in vector analysis and force problems