EntityQ15859323· pop 12· linked from 4 articlesAnne's theoremSign in to savetheorem in Euclidean geometryConnectionstriangleEntityInternational Standard Book NumberEntityWayback MachineEntityquadrilateralEntityparallelogramEntityEuclidean geometryEntitydiagonalEntityCambridge University PressEntityMathWorldEntityAmerican Mathematical SocietyEntitymidpointEntityEric W. WeissteinEntityNewton lineEntityCategoriesTheorems about quadrilaterals