Illuminator Beam Calculator
For an isosceles triangle with known apex angle θ (between the two equal legs) and the leg length a (the two legs are equal), this tool computes the base (third side). Formula: b = 2a·sin(θ/2).
Valid range: 0° < θ < 180°. Use the included angle at the apex.
This calculator assumes an isosceles triangle, so both legs are treated as equal to a.
Beam Diameter (Meters) = —
Using b = 2a·sin(θ/2). Equivalent by cosine rule: b = √(a² + a² − 2a²·cosθ).
Geometry preview (not to scale):
Green lines are the two legs; the dark base is the computed length b.
Results show up to 6 decimal places.
