Question

A hollow cylindrical pipe is made up of copper . it is 21 dm long .The outer and inner diameter of the pipe are 10cm and 6cm respectively. Find the volume of copper used in making the pipe ​

Answer 1

Step-by-step explanation:

To find volume of hollow cylinder.

The formula is volume =

h = 21dm

Convert dm to cm so h = 21*10 = 210cm

R = 10/2 = 5cm

r = 6/2 = 3cm

= 22/7

Therefore, Volume =

= 22*(25-9)*30 (cancelling 210 by 7)

=22*16*30 = 10560cu.cm()

Answer 2

Step-by-step explanation:

Volume of copper=volume of the hollow cylinder

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

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

                                              

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