OF垂直平分AD证明:∵AB∥DE,∴∠BAD=∠ADE∵AD平分∠BAC,∴∠BAD=∠CAD∴∠CAD=∠ADE,∴AF=DF连接OA,OD,则OA=OD∵OF=OF,∴△AOF≌△DOF(SSS)由图像可知△AOF和△DOF关於直线OF对称由对称的性质可知OF垂直平分AD
