trihedral l angle三面角

directed trihedral angle有向三面角

a trihedral angle三面角

supplementary trihedral angle补三面角

polar trihedral angle极三面角

oppositely directed trihedral angle反向三面角

birectangular trihedral angle双直三面角

monorectangular trihedral angle单直三面角

rectangular trihedral angle[数] 直三面角

trihedral angle reflector三面角反射器