解：?$(1) $?旋轉(zhuǎn)中心為點(diǎn)?$ A，$?旋轉(zhuǎn)角度為?$ 90°。$?
?$ (2) $?結(jié)論：?$△AEF $?是等腰直角三角形，理由如下：
?$ $?由旋轉(zhuǎn)的性質(zhì)可得?$ AF = AE，$??$∠F AB = ∠EAD$?
∵?$∠BAD = 90°$?
∴?$∠F AE = ∠F AB + ∠BAE = ∠BAE + ∠EAD = ∠BAD = 90°$?
又∵?$AF = AE，$?∴?$\triangle AEF $?是等腰直角三角形
?$ (3) $?結(jié)論：?$AE = DH $?且?$ AE⊥DH，$?理由如下：
?$ $?由題意知?$ AF = DH $?且?$ AF// DH$?
∴?$∠HGE = ∠F AE = 90°，$?∴?$AE⊥DH$?
∵?$AF = AE，$??$AF = DH$?
∴?$AE = DH，$?即?$ AE = DH $?且?$ AE⊥DH$?
