Answer:
125
Step-by-step explanation:
R = 4 cm , r = 2 cm
weight = 9.42 kg --> 9420 g
density = 6 g/cm³
9420g/volume cm³ = 6 g/cm³
9420/6 = volume
1570 = volume
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volume of a rod = 1570 cm³
πr²h = 1570
3.14×2×2×h = 1570
12.56×h = 1570
h = 125 cm
; length of the rod is 125 cm