問一題數學題

AD = DB (given)
DE//BC (given)
so AE = CE (intercept theroem)
2x = 6.6
x = 3.3

2008-02-23 15:10:02 補充：
樓上果個的答案令人摸不着頭腦= =

lf AD is n
AB：AD=2ｎ：１ｎ
AB：AD=2：１

DE：BC=6：3
DE：BC=2：1


ABC/ (：) ADE=2/ (：) 1
6.6/X=2/1
X=6.6/2
X=3.3