如图所示,已知EF⊥AB,OG为∠COF的平分线,OH为∠DOG的平分线, (1)若∠AOC:∠COF=4:7,求∠DOF的大小 (2)若∠AOC:∠DOH=8:29,求∠COH.

问题描述:

如图所示,已知EF⊥AB,OG为∠COF的平分线,OH为∠DOG的平分线,

(1)若∠AOC:∠COF=4:7,求∠DOF的大小
(2)若∠AOC:∠DOH=8:29,求∠COH.

(1)∵EF⊥AB,∴∠AOF=90°,∵∠AOC:∠COF=4:7,∴∠AOC=411∠AOF=411×90°=(36011)°,∵∠BOD=∠AOC∴∠DOF=∠FOB+∠BOD=90°+(36011)°=(135011)°,(2)∵∠AOC=∠DOB,∴∠DOB=90°-2COF=90°-2∠COG,...