Question

BO垂照垂直AO,OD平分角BOC,角AOC等于5/2角BOD,求角COD

Answer 1

∵BO⊥AO

∴∠AOB=90°

∴∠BOA(大角）=360°-90°=270°

∵OD平分∠BOC

∴∠BOC=2∠BOD

∵∠AOC=5/2∠BOD

∴∠AOC=5/4∠BOC

∵∠BOA(大角）=360°-90°=270°

∵∠BOA=∠AOC+∠BOC

即270°=5/4∠BOC+∠BOC

∴∠BOC=120°

∵∠BOC=2∠BOD

∴∠BOD120/2=60°