古尔丁定理

Pappus's centroid theorem

theorem that, for a solid of revolution of a planar figure, the surface area equals the figure’s perimeter times the distance the perimeter’s centroid travels, and the volume equals the figure’s area times the distance the figure’s centroid travels

古尔丁定理，最初由古希腊的帕普斯发现，后来在16世纪保罗·古尔丁又重新发现了这个定理。