KnowraBretschneider's formulaLinked fromLinked fromThe 5 pages that link to Bretschneider's formula, each with the reason it gives.All 5Related 3Narrower topic 1Compared with 1Ptolemy's theoremCompared with: Unlike Ptolemy's theorem, it applies beyond cyclic quadrilaterals and concerns area.QuadrilateralRelated: It generalizes Brahmagupta’s area formula to noncyclic quadrilaterals.Brahmagupta's formulaNarrower topic: It gives the general area relation from which Brahmagupta's cyclic case follows.Ptolemy's inequalityRelated: It addresses quadrilateral geometry through area and angles instead of a product inequality.Euler's quadrilateral theoremRelated: Together with Euler’s relation, it connects side and diagonal data to quadrilateral area.