挑战习题
1/5单选题
难度:

1.

如图,矩形ABCD的边长AB=6,BC=8,将矩形折叠,使点C与点A重合,则折痕EF长为(    )。




A

3

B

C

4

D

提示1:
PHA+6L+e57uTQUbvvIzmoLnmja7mipjlj6DnmoTmgKfotKjlvpfliLBFRuWeguebtOW5s+WIhkFD77yM5Y2zT0E9T0PvvIziiKBBT0Y9OTDCsO+8jOWImUZBPUZD77yM6K6+QUY9eO+8jOWImUZDPXjvvIxCRj1CQy14PTgteO+8jOWcqFJ04pazQUJG5Lit5qC55o2u5Yu+6IKh5a6a55CG5Y+v6K6h566X5Ye6eO+8jOWcqFJ04pazQUJD5Lit5qC55o2u5Yu+6IKh5a6a55CG5Y+v6K6h566X5Ye6QUM9MTDvvIzliJlPQT0177yM5ZyoUnTilrNBT0bkuK3liKnnlKjli77ogqHlrprnkIblj6/orqHnrpflh7pPRu+8m+aYk+ivgeW+l+KWs0FPReKJjOKWs0NPRu+8jOW+l+WIsE9FPU9G77yM5YiZRUY9Mk9GLjwvcD4=
正确答案:Qg==
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