Question

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

Answer 1

∵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.