Bonjour,
1) P = 2¹⁹ cm
a) c = P/4 = P/2² = 2¹⁹/2² = 2¹⁹ ⁻ ² = 2¹⁷ cm
b) A = c² = (2¹⁷)² = 2³⁴ cm²
2) A = 19¹² cm² et A = c²
⇒ c = √(A) = √(19¹²) = 19⁶ cm
3) c = 6.10⁻⁹ m
a) Aface = c² = (6.10⁻⁹)² = 36.10⁻¹⁸ m²
b) V = c³ = (6.10⁻⁹)³ = 6³ x (10⁻⁹)³ = 216.10⁻²⁷ m³
4) V = 7.10¹⁵ dm³
V = c³ ⇒ c = ∛(V) = ∛(7.10¹⁵) = ∛(7) x ∛(10¹⁵) = ∛(7) x 10⁵ dm