Apatrat=10x10=100 m²
2L+2l=70
L+l=35 ⇒ L=35-l
latimea micsorata = l/3
Lxl/3 =100
(35-l) x l/3=100
35l-l²=300
l²-35l+300=0
Δ=1225-1200=25
l₁=(35+√25)/2=(35+5)/2=20
l₂=(35-√25)/2=(35-5)/2=15
L=20 m
l=15 m
verificare
P=2(20+15)=70 m
2.Abaza cub=64 dm²
cubul are 6 fete
Alaterala =4x64=256 dm²
Atotala = 6x64=384 dm²