Home›Theorems about quadrilaterals›ペトル=ダグラス=ノイマンの定理🌐日本語EnglishEspañolFrançais中文日本語EntityQ7179251· pop 7· linked from 6 articlesペトル=ダグラス=ノイマンの定理Also known as PDN-theorem, Douglas’s theorem, Douglas–Neumann theorem, Napoleon–Douglas–Neumann theorem, Petr’s theoremWikidata factsShow 1 more factCommons categoryPetr–Douglas–Neumann theoremvia Wikidata · CC0Available in 6 languagesFrançais中文日本語CzechHebrewvia Wikidata sitelinks · CC0ConnectionspentagonEntityPragueEntityCategoriesTheorems about quadrilaterals