Law of Sines Calculator — Triangle Solver with Ambiguous Case

Solve triangles using the law of sines. Handles AAS, ASA, and SSA configurations including the ambiguous case with 0, 1, or 2 solutions.

Two solutions (Ambiguous case) ⚠ Ambiguous case detected

Solution 1

Side a
7.0000
Opposite angle A = 30.0000°
Side b
10.0000
Opposite angle B = 45.5847°
Side c
13.5592
Opposite angle C = 104.4153°
Area
33.8981
Via Heron's formula
Common Ratio
14.0000
a/sin(A) = b/sin(B) = c/sin(C) = 2R
Circumradius R
7.0000
R = ratio / 2
Inradius r
2.2185
r = Area / s
Triangle Type
Scalene Obtuse
Classified by sides and angles
a = 7.00
b = 10.00
c = 13.56

Solution 2

Side a
7.0000
Opposite angle A = 30.0000°
Side b
10.0000
Opposite angle B = 134.4153°
Side c
3.7613
Opposite angle C = 15.5847°
Area
9.4032
Via Heron's formula
Common Ratio
14.0000
a/sin(A) = b/sin(B) = c/sin(C) = 2R
Circumradius R
7.0000
R = ratio / 2
Inradius r
0.9058
r = Area / s
Triangle Type
Scalene Obtuse
Classified by sides and angles
a = 7.00
b = 10.00
c = 3.76

Detailed Comparison (Both Solutions)

PropertySolution 1Solution 2
Side a7.00007.0000
Side b10.000010.0000
Side c13.55923.7613
Angle A (°)30.000030.0000
Angle B (°)45.5847134.4153
Angle C (°)104.415315.5847
Area33.89819.4032
Perimeter30.559220.7613
Circumradius R7.00007.0000
Inradius r2.21850.9058
Common Ratio14.000014.0000
TypeScalene ObtuseScalene Obtuse

SSA Ambiguous Case Reference

ConditionSolutionsExplanation
a < b·sin(A)0Side a is too short to form a triangle
a = b·sin(A)1Exactly one right triangle
b·sin(A) < a < b2Ambiguous — two possible triangles
a ≥ b1Unique triangle
Your case2Two solutions (Ambiguous case)
Planning notes, formulas, and examples

About the Law of Sines Calculator — Triangle Solver with Ambiguous Case

The **Law of Sines Calculator** solves triangles using the relation a/sin(A) = b/sin(B) = c/sin(C). It accepts three standard configurations: AAS (two angles and a non-included side), ASA (two angles and the included side), and the notoriously tricky SSA case (two sides and a non-included angle) where zero, one, or two valid triangles may exist.

The ambiguous SSA case is the most interesting feature of this calculator. When two sides and a non-included angle are given, the calculator determines whether the data produces zero solutions (the shorter side cannot reach the opposite side), exactly one solution, or two distinct solutions. When two solutions exist, both are fully computed and displayed side by side so you can compare them.

For every valid solution, the calculator outputs all three sides, all three angles, the area (by Heron's formula), the perimeter, the common sine-ratio constant (a/sin A), the circumradius (R = ratio/2), the inradius, and a triangle-type classification. Side-proportion bars provide a visual comparison of the three sides. A detailed comparison table shows all properties for one or both solutions when the ambiguous case arises.

A reference table explains the four conditions of the SSA case with clear thresholds and highlights which condition matches your current input. Eight preset buttons load common configurations — including classic 30-60-90 and 45-45-90 triangles, ASA examples, and carefully chosen SSA cases that demonstrate zero-solution, one-solution, and two-solution scenarios.

When This Page Helps

Law of Sines Calculator — Triangle Solver with Ambiguous Case helps you avoid repetitive setup mistakes when solving trigonometric and coordinate-geometry problems. Instead of recalculating conversions, signs, and edge cases by hand, you can test inputs immediately, inspect intermediate values, and confirm final answers before submitting work or using numbers in downstream calculations. It surfaces key outputs like Side a, Side b, Side c in one pass.

How to Use the Inputs

  1. Enter the required inputs (Configuration, Angle B (°), Side b).
  2. Complete the remaining fields such as (Side c is the included side), Decimal Precision.
  3. Review the output cards, especially Side a, Side b, Side c, Area.
  4. Compare the result with the formula, diagram, or example values to catch sign, unit, or rounding mistakes.
Formula used
a/sin(A) = b/sin(B) = c/sin(C). In SSA: sin(B) = b·sin(A)/a. If sin(B) > 1, no solution; if sin(B) = 1, one right triangle; if sin(B) < 1, check B₁ and B₂ = 180°−B₁ for the ambiguous case.

Example Calculation

Result: Two solutions: B₁ ≈ 45.58°, B₂ ≈ 134.42°

Using a=7, b=10, A=30°, the calculator returns Two solutions: B₁ ≈ 45.58°, B₂ ≈ 134.42°. This example mirrors the calculator's live computation flow and is useful for checking manual steps and unit handling.

Tips & Best Practices

  • The SSA (side-side-angle) case is the only configuration that can be ambiguous.
  • When a ≥ b in SSA, the solution is always unique.
  • The common ratio a/sin(A) equals 2R, where R is the circumradius.
  • AAS and ASA always produce a unique solution (if angles sum to less than 180°).
  • The law of sines is most useful when you know an angle-opposite-side pair.

What This Law of Sines Calculator — Triangle Solver with Ambiguous Case Solves

This calculator is tailored to law of sines calculator — triangle solver with ambiguous case workflows, including common input modes, unit handling, and special-case behavior. It is designed for fast checking during homework, exam preparation, technical drafting, and coding tasks where trigonometric consistency matters.

How To Interpret The Outputs

Use the primary result together with supporting outputs to verify direction, magnitude, and validity. Cross-check against known identities or geometric constraints, and confirm that angle ranges, sign conventions, and domain restrictions are satisfied before using the numbers elsewhere.

Study And Practice Strategy

A reliable way to improve is to solve once manually, then verify with the calculator and explain any mismatch. Repeat this on varied examples and edge cases. The built-in preset scenarios for quick trials, comparison tables for side-by-side validation, visual cues that make trends and quadrants easier to read help you build pattern recognition and reduce sign or conversion errors over time.

Sources & Methodology

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Frequently Asked Questions

  • The law of sines states that a/sin(A) = b/sin(B) = c/sin(C), meaning the ratio of each side to the sine of its opposite angle is constant for any triangle.