更新时间2018-03-12 08:42:25
解 :∵ON是∠COD的平分线 ; OM是∠AOD的平分线
∴∠CON=∠DON ;∠AOM=∠MOC+∠CON+∠DON=∠MOC+∠CON
∵CO⊥AB
∴∠AOC=90º
∴2(∠CON+∠MOC)=90º ∴∠CON+∠MOC=45º
∴∠MON=45º
∠MON=∠MOC+∠CON=∠AOC-∠AOM+∠CON=90°-∠AOM+∠CON
=90°-∠MOD+∠CON=90°-(∠AOC+∠COD)/2+∠CON
=90°-(90°+∠COD)/2+∠CON=90°-(45°+0.5∠COD)+∠CON
=90°-(45°+0.5∠COD)+0.5∠COD
=90°-45°-0.5∠COD+0.5∠COD
=90°-45°
=45°
回答完毕保证正确
∠MON=∠DOM-∠DON=1/2∠DOA-1/2∠DOC=1/2∠AOC=1/2*90=45