EntityQ4117142· pop 9· linked from 17 articlesLambert quadrilateralSign in to savequadrilateral with three right anglesConnectionsangleEntitygeometryEntityInternational Standard Book NumberEntityquadrilateralEntityIbn al-HaythamEntityEuclidean geometryEntityright angleEntityhyperbolic functionEntitynon-Euclidean geometryEntityhyperbolic geometryEntityparallel postulateEntityelliptic geometryEntityGaussian curvatureEntityfundamental domainEntitySaccheri quadrilateralEntityCategoriesHyperbolic geometryTypes of quadrilaterals