Home›Constant width›Barbier's theorem🌐EnglishEnglishDeutschEspañolFrançaisItalianoNederlandsPolskiPortuguêsTürkçeРусский한국어日本語EntityQ1188048· pop 15· linked from 15 articlesBarbier's theoremAlso known as Melish's theoremtheorem that every curve of constant width has perimeter π times its widthAvailable in 15 languagesEspañolFrançaisDeutsch日本語РусскийPortuguêsItalianoArmenianEsperantoPolskiRomanianConnectionsgeometryEntityPiConceptCategoriesConstant widthLengthPiTheorems in plane geometry