EntityQ919125· pop 30· linked from 86 articlesparallelogram lawSign in to savemathematical theoremConnectionsinner product spaceEntityangleEntityPythagorean theoremEntitynormed vector spaceEntityLp spaceEntityconvex coneEntityweak topologyEntityreflexive spaceEntitymathematicsEntitygeometryEntityInternational Standard Book NumberEntitycomplex numberEntityreal numberEntityrectangleEntityquadrilateralEntitydigital object identifierEntityparallelogramEntityintegralEntityderivativeEntityEuclidean geometryEntityCategoriesEuclidean geometryTheorems about quadrilaterals