Question

how much iron is required to make iron bar whose length is 9cm and diameter is 1.4cm.​

Answer 1

just calculatate the volume depending on the shape

for an iron bar

pie*r*r*h

13.16(13cm approx)

Answer 2

formula of volume of cylinder is

$\pi \: r \times \: r \: \times h \\ \: so \: \pi \times 0.7 \times 0.7 \times 9 \\ \: 3.14 \times 0.7 \times 0.7 \times 9 \\ \: = 13.84 \\ \: cu.cm \: iron \: will \: be \: used$