Reckoning / Shape / Ring sector
Plane figure · Circles
Ring sector
A slice of an annulus, like a curved tile or a voussoir of an arch.
Dimensions
Results
area A
Formulas
The same fraction θ/360° of the whole annulus.
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.