如图,在三角形ABC中,AD/DB=AE/EC,AB=12,AE=6,EC=4

∵BD=AB-AD=12-AD,
AD/BD=AE/EC,
∴AD/(12-AD)=6/4=3/2,
∴2AD=36-3AD,
AD=36/5=7.2,
⑵由⑴得BD=AB-AD=12-7.2=4.8,
∴DB/AB=4.8/12=0.4,
EC、AC=4/10=0.4
∴BD/AB=EC/AC.