梯形ABCD中,DC∥AB,E為腰BC的中點(diǎn),若AB=8,CD=2,AE把梯形分為△ABE和四邊形ADCE,它們的周長(zhǎng)相差4,則梯形的腰AD的長(zhǎng)為( )
A. 12
B. 10
C. 2或10
D. 2或12
![](http://hiphotos.baidu.com/zhidao/pic/item/377adab44aed2e737ca2a59b8401a18b87d6fa3a.jpg)
∵△ABE的周長(zhǎng)是:AB+AE+BE=8+AE+BE;
四邊形ADCE的周長(zhǎng)是:AD+CD+CE+AE=AD+2+AE+CE,
根據(jù)題意得:(8+AE+BE)-(AD+2+AE+CE)=4或(AD+2+AE+CE)-(8+AE+BE)=4;
又∵BE=CE
即:AD=4或AD+2-8=4
解得AD=2或10.
故選C.