Trigonometry

Law of Sines (side)

Side b given a, angle A, angle B.

Formula

Formula
b = a · sin Bsin A

Variables

SymbolDefinitionType & rangeUnitsRole
a known side real number (ℝ) input
A, B angles (deg) real number (ℝ) deg input

Try it yourself

Interactive calculator
Result

Worked examples

Example 1
Givena = 10, angle A (deg) = 30, angle B (deg) = 45
Result14.14213562
Example 2
Givena = 7, angle A (deg) = 40, angle B (deg) = 60
Result9.431074487