Ex 4:
AB=20cm
MB=4cm
AM=AB-MB-20-4=16cm
Daca MN || BC => M,N sunt la distante egale pe dreptele AB,AC => AM=AN; MB=NC => NC=MB=4cm
Ex 5:
AB=18cm
AM=7cm
MN=4cm
Triunghiurile ABC si MNC sunt asemenea => [tex]\frac{MN}{AB} = \frac{AM}{AC}= \frac{NB}{BC}=>\frac{4}{18} = \frac{7}{AC}=\frac{NB}{BC} => AC=\frac{18*7}{4} => AC=31.5cm[/tex]
