∵OD平分∠AOC
∴∠AOD=∠COD
设∠AOD为x°,∠COD为x°
x+x+40°=180°
2x=140°
x=70°
∵∠AOD=x
∠AOE=∠ODE-∠AOD
=90°-70°
=20°
∴∠AOE=20°