正弦定理計算機

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はじめに

Law of Sines Calculator — Solve a triangle side using the law of sines. Enter Side a, Angle A (degrees, opposite a), Angle B (degrees) to get an instant, accurate result.

計算式

Law of sines: a/sin(A) = b/sin(B). Given side a and its opposite angle A, and a second angle B, side b = (a/sin(A)) × sin(B).

ステップごとの説明

Enter the Side a.
Enter the Angle A (degrees, opposite a).
Enter the Angle B (degrees).
Click Calculate to see your result instantly.

実例

Example: With Side a = 10, Angle A (degrees, opposite a) = 30, Angle B (degrees) = 90, the Law of Sines Calculator gives Ratio: 20, Side B: 20.

よくある質問

What information do I need?

One side, its opposite angle, and a second angle — the calculator then finds the side opposite that second angle.

Does this work for any triangle?

Yes, the law of sines applies to any triangle, not just right triangles.

What inputs does the Law of Sines Calculator need?

You'll need to provide: Side a, Angle A (degrees, opposite a), Angle B (degrees). All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.

How accurate is the Law of Sines Calculator?

The Law of Sines Calculator applies the formula exactly as calculated — Law of sines: a/sin(A) = b/sin(B). Given side a and its opposite angle A, and a second angle B, side b = (a/sin(A)) × sin(B). — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.

Is the Law of Sines Calculator free to use?

Yes, the Law of Sines Calculator is completely free, requires no signup, and runs instantly in your browser.