如图：
∵∠A+∠ABC+∠ACB=180°，∠A=40°
∴∠ABC+∠ACB=140°
又∵∠ABC+∠EBC=180°，∠ACB+∠FCB=180°
∴∠FCB+∠EBC=180°+180°-140°=220°
又∵角B,角C的外角平分线交于点D
∴∠DBC+∠DCB=110°
又∵∠DBC+∠DCB+∠D=180°
∴∠D=70°
