Question

how much iron is needed to make a rod of length 90 cm and diameter 1.4 cm?​

Answer 1

Answer:

Iron needed is 138.3 cm^3 or 138.3 g

Step-by-step explanation:

Amount of iron needed = Volume of the Iron rod

Rod is cylindrical in shape, so it's volume = πr^2h

Now, r = d/2 = 1.4/2

$= \frac{22}{7} \times ({ \frac{1.4}{2} })^{2} \times 90 \\ = \frac{22}{7} \times \frac{1.4}{2} \times \frac{1.4}{2} \times 90 \\ = 138.3 \: {cm}^{3}$