a) In ΔADB, DM =mediatoare si inaltime, dar si mediana. Acest lucru se intampla doar intr-un triunghi isoscel. Atunci ΔADB=isoscel ⇒[AD]≡[BD].
b) Pdab=25cm si Pdam=19cm
Pdab=DA+AB+DB=DA+AM+MB+DB
Dar [AM]≡[MB]
Iar [AD]≡[BD]
Atunci Pdab=2DA+2AM=25cm ⇒2(DA+AM)=25cm ⇒DA+AM=25/2cm=12,5cm.
c) Iar Pdam=DA+AM+DM=19cm
Inlocuim
12,5+DM=19
DM=19-12,5
DM=6,5cm.