Law of Sines Calculator
Use the law of sines to find a missing side or angle — including both answers when two triangles fit.
Side b
11.27971695
- Angle C
- 75°
- Side c
- 12.02171058
- a ÷ sin A (= 2 × circumradius)
- 12.44579061
Show the work
Law of sines: every side ÷ the sine of its opposite angle is the same number k
k = a ÷ sin A
8 ÷ sin 40° = 12.44579061
Side b = k × the sine of its opposite angle
b = k × sin B
12.44579061 × sin 65° = 11.27971695
How it works
a ÷ sin A = b ÷ sin B = c ÷ sin C
Questions
- How does the law of sines calculator work?
- a ÷ sin A = b ÷ sin B = c ÷ sin C.
- What do I need to enter?
- Find, Side a, Angle A, Angle B, Side b. Optional fields can be left blank.
Related tools
- Law of Cosines CalculatorUse the law of cosines to find the third side from two sides and the angle between them, or any angle from three sides.
- Distance Calculator (2D & 3D)Find the straight-line distance between two points on a plane or in 3D space.
- Midpoint CalculatorFind the midpoint between two points in 2D or 3D.
- Slope & Line Equation CalculatorFind the slope through two points and the line's equation in slope-intercept, point-slope and standard form.
- Trapezoid CalculatorFind a trapezoid's area and median from its two bases and height, plus the perimeter if you know the legs.
- Parallelogram & Rhombus CalculatorFind the area, perimeter, height and diagonals of a parallelogram, or a rhombus from its diagonals.
Want this on your site? Embed the law of sines calculator.