Stadium (geometry)

A stadium is a two-dimensional geometric shape constructed of a rectangle with semicircles at a pair of opposite sides. Alternative names include discorectangle and obround.

A capsule is produced by revolving a stadium around the line of symmetry that bisects the semicircles.

The shape is used for athletics and horse racing tracks.

The perimeter of a stadium is calculated by the formula ${\displaystyle P=2(\pi r+a)}$ and the area by ${\displaystyle A=\pi r^{2}+2ra=r(\pi r+2a),}$ where a is the length of the straight sides and r is the radius of the semicircles.

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