Fie DM⊥AC
d(D,AC)=DM
BC=15 cm
AC=12 cm
BC=BD+DC
15=BD+2BD
15=3BD
BD=5 cm
DC=10 cm
Aplicam Pitagora
BC²=AC²+AB²
AB²=225-144=81
AB=9 cm
DM║AB
ΔCMD si ΔCAB dreptunghice⇒T.F.A⇒
[tex]\frac{CD}{CB} =\frac{CM}{CA} =\frac{DM}{AB}\\\\\frac{10}{15} =\frac{DM}{9}[/tex]
DM=90:15=6 cm
Raspuns: d(D,AC)=6 cm