bonjour,
1) V = pi*0,5²*h
= 0,25pi*h(cm^3)
2) V = 4/3(pi*30^3)
= (4*pi*27000)/3
= 36000pi(cm^3)
on convertit 0,5mm en cm = 0,05cm
la ficelle a tjs 0,05cm de rayon
on sait que pi*0,05²*h = 36000
pi*0,0025*h = 36000
h = 36000/0,0025 = 14400000cm soit 144000m soit 144km
