Reckoning / Shape / Circular sector
Plane figure · Circles
Circular sector
A slice of a disc between two radii.
Dimensions
Results
area A
arc length l
Formulas
The sector is the fraction θ/360° of the whole disc; in radians the area is simply r²θ/2.
Checked: the A formula agrees with a Monte Carlo measurement of the shape itself, made from its geometric definition, every time the site is built.
Topology lens
Topologically a disc, like every figure here without a hole: Euler characteristic 1. Stretching turns it into a circle, a square or a star. More on the lens.