Răspuns:
1. |___|____|
A M B
AM= AB- MB= 2,8- 1,9= 0,9 cm
2. |___M___|__N__| AB= 6 BN= 2
A B C
M mijl lui AB=> AM=BM= 6:2 = 3 cm
N mijloc lui BC => BN= NC= 2
BC= NC+ BN= 2+2= 4 cm
AC= AB+BC= 6+4= 10 cm
3. |___|____|____|___|
O A B C X
AB=5 AC = 10
daca B mijl lui AC => AB= BC
BC= AC- AB= 10 -5= 5 cm => B mijl lui AC
M mijl lui AB => MB=AM= 5:2= 2,5 cm
N mij lui BC=> NB= NC= 5:2= 2.5 cm
MN= MB+BN= 2.5+2.5= 5 cm
