(1)设∠AOE=x
则∠AOD=3x=∠COB
∠DOF=4x=∠COE
则4x+3x+x=180
解得x=22.5°
∠AOD=67.5°
∠EOD=22.5° +67.5° =90°
(2) ∠EOD=90°
所以CD与EF垂直关系