Réponse :
t = 1,25h = 1h15min (0,25h = 1/4h = 15min)
t = 2h45 min = 2,75h (45min = 3/4h = 0,75h)
v = 12km/s= 720km/min (12km/s = 12km × 60/1s × 60 = 720km/60s = 720km/min)
1 = 3456m = 3,456km
V = 345m³ = 345000dm³
v = 2m/s = 7,2km/h (2m/s = 2m × 3600/1s × 3600 = 7200m/3600s = 7,2km/h)