Question

如图，∠AOB＝∠COD＝90⁰,OC平分∠AOB，∠BOD＝3∠DOE。

试求 ∠COE的度数。

 

Answer 1

 解：∵∠AOB＝90⁰，OC平分∠AOB

       ∴∠BOC＝∠AOB＝45⁰                          

       ∵∠BOD＝∠COD-∠BOC＝90⁰-45⁰＝45⁰

              ∠BOD＝3∠DOE                                      

∴∠DOE＝15⁰                                                                         

 ∴∠COE＝∠COD-∠DOE＝90⁰-15⁰＝75⁰