如圖,矩形ABCD的兩邊BC、CD分別在x軸、y軸上,點(diǎn)C與原點(diǎn)重合,點(diǎn)A(﹣1,2),將矩形ABCD沿x軸向右翻滾,經(jīng)過一次翻滾點(diǎn)A對應(yīng)點(diǎn)記為A1 , 經(jīng)過第二次翻滾點(diǎn)A對應(yīng)點(diǎn)記為A2…依此類推,經(jīng)過5次翻滾后點(diǎn)A對應(yīng)點(diǎn)A5的坐標(biāo)為( )
請同學(xué)們在下面的橫線上把解答過程補(bǔ)充完整:
解:∵ EF//AD,(已知)
∴ ∠2=∠3, ( )
又∵ ∠1=∠2, (已知)
∴ ∠1=∠3, (等量代換)
∴ ▲ , (內(nèi)錯角相等,兩直線平行)
∴ ∠B+∠BDG=180°, ( )
∵ ∠B=55°, (已知)
∴ ∠BDG = ▲ .
①;
②;