Question

a hollow cylindrical pipe is made up of copper. it is 21cm long, the outer and inner diameter of pipe are 10cm and 6cm respectively. find volume of copper used in making of pipe.​

Answer 1

Step-by-step explanation:

volume of copper=volume of the hollow cylinder

volume of hollow cylinder=\piπ R^2*h-\piπ r^2*h(R=outer radius,r=inner radius,h=height)

R=10/2cm=5cm r=6/2cm=3cm h=21dm=210cm(1dm=10cm)

volume of copper=\piπ *h(R^2-r^2)=22/7*210*(5^2-3^2)[210/7=30]

=22*30*(25-9)=660*16

=10506cu.cm

Answer 2

$\frac{22}{7} \times 21 \times ( {5}^{2} - {3}^{2} ) \\ \frac{22}{7} \times 21 \times 4 \\ = 264 {cm}^{3}$