Т.к. ∠AOB=∠DOE, ∠BOC=∠COD, то:
1) ∠AOB+∠BOC=∠DOE+∠COD => ∠AOC=∠COE
2) Т.к. ∠AOD=∠AOB+∠BOC+∠COD, ∠BOE=∠DOE+∠BOC+∠COD => ∠AOD=∠BOE
