(2)∠CPD与∠PDO ,∠BDO与∠PCA,∠PCO与∠DPO；∠BDP与∠PCO.
(3)∠DPC与∠PDB,∠BDP与∠DOC,∠DPC与∠PCA,∠ACP与∠COB,∠CPO与∠DOC,∠PDO与∠PCO.