Bonjour,
a) 1 année = 365 jours = (365 × 24) h = (365 × 24 × 3 600) s
3 × 10⁵ × 3 600 × 24 × 365
= 3×10⁵ × 3,6×10³ × 2,4×10¹ × 3,65×10²
= (3 × 3,6 × 2,4 × 3,65) × 10⁵⁺³⁺¹⁺²
= 94,608 × 10¹¹
= 9,4608 × 10¹²
≅ 9,5 × 10¹² (km)
b) 9,5 × 10¹² × 5 000
= 9,5 × 10¹² × 5 × 10³
= (9,5 × 5) × 10¹²⁺³
= 47,5 × 10¹⁵
= 4,75 × 10¹⁶ (km)
