.∠AOC + ∠AOD = 180° ∠AOC=∠AOD-80° 解得：∠AOC = 50°,∠AOD = 130° ∠DOE = 1/2 * ∠BOD = 1/2 * ∠AOC = 25° ∠AOE = ∠AOD + ∠DOE = 155°
