KnowraParallelogram lawLinked fromLinked fromThe 8 pages that link to Parallelogram law, each with the reason it gives.All 8Related 6Compared with 2Hilbert spaceRelated: A norm satisfies this law exactly when it can be induced by an inner product.ParallelogramRelated: Its vector form expresses the diagonal-side relationship for parallelograms.Van Aubel's theoremCompared with: It gives a related vector-length identity, but Van Aubel's conclusion concerns opposite square centers.Euler's quadrilateral theoremRelated: Applying this identity to paired sides produces the theorem’s diagonal and midpoint terms.Apollonius's theoremRelated: A parallelogram construction turns the median identity into a direct instance of this law.British flag theoremRelated: Its vector form gives the same diagonal-sum identity for a rectangle.Finsler–Hadwiger theoremRelated: The identity supplies the equal-length relation behind the theorem’s third square.Riesz's lemmaCompared with: The lemma needs only norm axioms, not the inner-product geometry characterized by this law.