A segment of a circle is a region bounded by an arc and the chord connecting the arc's endpoints. Unlike a sector (which includes the center), a segment only captures the curved "slice" of the circle without extending to the center. Segments are commonly seen in circular windows, arches, and mechanical components.
This formula calculates the area enclosed by an arc and a chord:
\[ A = \frac{r^2}{2} \left( \frac{\pi \alpha^\circ}{180^\circ} - \sin(\alpha^\circ) \right) \]
where: