23.已知直線AB,CD被直線MN所截,交點(diǎn)分別為點(diǎn)E,F(xiàn),且∠AEF+∠DFN=180°.
(1)如圖1,請說明AB與CD的位置關(guān)系;
(2)如圖2,點(diǎn)P,Q分別在射線EM,F(xiàn)N上,點(diǎn)G,H分別在射線EA,F(xiàn)C上,連接PG,QH,并分別延長交于點(diǎn)O,且∠PGE+∠QHF=90°,求∠POQ的度數(shù);
(3)如圖3,在(2)的條件下,連接OF.若OF平分∠POQ,且FM平分∠DFO,∠DFE=5∠EGP,求∠OPQ的度數(shù).