Question

a hollow cylindrical pipe is made up of copper the volume of the metal used in the pipe is 2640 cubic cm its external radius is 7cm and length of the wire so obtained

Answer 1

hey kavi :))
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this is a well asked question and i too solved it earlier

so as uh have forgot to say the length so i may tell uh brother..then length is 21 cm.

so heres your solution  just pay attention brother :))//

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r=7cm
l=21cm
 

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volm of hollow cy. πh(R²-r²)
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therefore. putting values.

2640= 22÷7 ×21(49-r²)
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on smpilfying we get;

r=3cm
R=7-3
R=4cm
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hope it helps you
thanks!!!
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