Notam Δ cu "ABC".
PΔ=AB+BC+AC
a)Fie AB=BC
->Cand AB=40m=>BC=40m
=>PΔ=AB+AB+AC
96=40+40+AC
96-80=AC
AC=16
->Cand AC=40m
96=AB+AB+40
96-40=2AB
56=2AB
AB=28m=>BC=28m
b)Fie BC=AC
->Cand AB=40m
PΔ=AB+BC+BC
PΔ=AB+2BC
96=40+2BC
56=2BC
BC=28m=>AC=28m
->Cand BC=40m
PΔ=AB+BC+BC
96=AB+80
AB=16m
c)Fie AB=AC
->Cand AB=40
PΔ=AB+BC+AB
96=80+BC
BC=16m
->Cand BC=40m
PΔ=2AB+BC
96=40+2AB
56=2AB
AB=28m=>AC=28m