(1)旋转中心为点A;
(2)∵AB与AD为对应边,
∴∠BAD等于旋转角,
∴旋转角度是90°;
(3)连EF,如图,在Rt△ADE中,AE=
=
=
,
∴ADE旋转后能与△ABF重合.
∴∠FAE=∠BAD=90°,AE=AF,
∴EF=
AE=
×
=
.
(1)旋转中心为点A;
(2)∵AB与AD为对应边,
∴∠BAD等于旋转角,
∴旋转角度是90°;
(3)连EF,如图,在Rt△ADE中,AE=
=
=
,
∴ADE旋转后能与△ABF重合.
∴∠FAE=∠BAD=90°,AE=AF,
∴EF=
AE=
×
=
.