a) A fata = A patrat = 16 cm²
A patrat = l²
l² = 16
l² = 4² ⇒ l = 4 cm
V cub = l³ = 4³ = 64 cm³
b) P fata = P patrat = 20 dm
P patrat = 4l
4l = 20
l = 20/ 4
l = 5 dm
V cub = l³ = 5³ = 125 dm³
c) Suma lungimilor 36 cm
Cubul are 12 muchi.
S = 36
l cub = muchia cub = 36 ; 12
l cub = 3 cm
V cub = l³ = 3³ = 27 cm³
d) Suma ariilor tuturor fetelor = 24 dm²
Cubul are 4 fete laterale, adica 4 patrate.
4 · A fata = 24
A fata = 24 ; 4 = 6 dm², aria unui patrat
A fata = l²
l² = 6
l = √6 dm
V cub = l³ = ( √6)³ = 6√6 dm³