A hollow cylinder tube 20 cm long is made of iron and its external and internal diameter are 8 cm and 6 CM respectively the volume of iron used in making the tube is what
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Answer:
140 cm³
Step-by-step explanation:
Find the volume with diameter = 8 cm
Radius = Diameter ÷ 2
Radius = 8 ÷ 2 = 4 cm
Volume = πr²h
Volume = π(4)²(20) = 320π cm³
Find the volume with diameter = 6 cm
Radius = Diameter ÷ 2
Radius = 6 ÷ 2 = 3 cm
Volume = πr²h
Volume = π(3)²(20) = 180π cm³
Find the volume of the iron:
Volume = 320 - 180 = 140 cm³
Answer: 140 cm³
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ALTERNATIVE SOLUTION (Shortcut):
Volume = π(R1² - R2²)h
Volume = π(4² - 3²)(20) = 140 cm³
Answer: 140 cm³
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