题目如图,AB,AB,AB∥CDCDCD,DF=EFDF=EFDF=EF,AB=12AB=12AB=12,CD=9CD=9CD=9,则AEAEAE等于______.知识点：梯形中位线定理的证明章节：未标注
如图∥,,,,则等于______.如图∥,,,,则等于______.如图∥,,,,则等于______.