證明：?$(1)$?在?$△ABC$?和?$△ADE$?中
?$\begin {cases}{∠BAC=∠DAE}\\{AB=AD}\\{∠B=∠D}\end {cases}$?
∴?$△ABC≌△ADE(\mathrm {ASA})$?
?$(2)$?∵?$△ABC≌△ADE$?
∴?$AC=AE$?
而?$∠BAC=∠DAE$?，?$AB=AD$?
∴將?$△ADE$?繞著點?$A$?按逆時針方向旋轉(zhuǎn)一個銳角后與
?$△ABC$?重合，則?$AD$?與?$AE$?重合，?$AE$?與?$AC$?重合
∴?$∠EAC$?等于旋轉(zhuǎn)角，即旋轉(zhuǎn)角度為?$25°$?
