EntityQ1896455· pop 22· linked from 17 articlesVarignon's theoremSign in to savetheorem that the midpoints of the sides of an arbitrary quadrilateral form a parallelogramConnectionstriangleEntityareaEntityInternational Standard Book NumberEntityangleEntitylinear algebraEntityrectangleEntitypolygonEntityquadrilateralEntityrhombusEntitydigital object identifierEntityparallelogramEntitytrapezoidEntityEuclidean geometryEntityperimeterEntityperpendicularityEntityif and only ifEntityMathWorldEntityaffine geometryEntityconvex polygonEntitycentroidEntityCategoriesEuclidean geometryTheorems about quadrilaterals