Question

帮帮我呗！

Answer 1

角AOC＋角BOC＝180＝角AOC＋2角AOC＝3角AOC＝180
角AOC＝60
角DOF＝角EOC＝角AOC－角AOE＝60-40＝20

Answer 2

∠AOC+∠BOC=180
∠BOC=2∠AOC
∠AOC+2∠AOC=180
∠AOC=60
∠DOF=∠COE=∠AOC-∠AOE=60-40=20