∠COB=2∠AOC,∠AOD=∠BOD,且∠CO - 知识问答

∠COB=2∠AOC,∠AOD=∠BOD,且∠COD=19°则∠AOB为多少度?

1个回答

∵OD平分∠AOB
∴∠BOD=∠AOD
∵∠COB=2∠AOC
∴∠BOD+∠COD=2∠AOC
∵∠COD=19°
∴∠BOD+19°=2∠AOC
∵∠BOD=∠AOD且∠AOD=∠AOC+19°
∴∠AOC+19+19°=2∠AOC
∴∠AOC=38°
∴∠AOD=38°+19°=57°
∴∠AOB=2∠AOD=57°x2=114°

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