Se da triunghiul ABC, D apartine (AB), E apartine (AC) si DE||BC . e) Daca AC=14 cm, AD=2,5 cm, DE=4cm si BC=16cm, calculati AE,AB,DB,EC.

Răspuns:
∆ABC≈ ∆DEdeoareceDE ll BC
=>rapoartele de asemănare
AD/AB=AE/AC=DE/BC
2,5/(BD+2,5)=AE/14=4/16=1/4
AE=14/4=7/2cm=3,5cm
BD+2,5=4×2,5=10
BD=10-2,5=7,5cm
AB=7,5+2,5=10cm
EC=14-3,5cm=10,5cm