如图,AA'//BB'//CC'//DD',且AB=BC=CD,A'B'=B'C'=C'D',AA'=3/DD'=6,求BB'和CC'的长
问题描述：
如图,AA'//BB'//CC'//DD',且AB=BC=CD,A'B'=B'C'=C'D',AA'=3/DD'=6,求BB'和CC'的长
答
ADD'A'与BCC'D'中位线相等为4.5,所以BB'+CC'=9,设BB'为X,CC'为Y
X+Y=9
6+X=2Y
解得X=4,Y=5