Question

A hollow cylindrical pipe is 21 dm long. Its outer and inner diameters are 10cm and 6cm respectively. Find the volume of the copper used in making the pipe.

Answer 1

Answer:

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Answer 2

${\huge{\underline{\underline{\sf{\red{Solutions:-}}}}}}$

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Length of hollow cylindrical copper pipe = 21dm

➡ ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀h = 21 dm = 210cm

Its ⠀⠀⠀⠀Outer diameter=10cm ➡ Outer radius,

$R = \frac{10}{2} = 5cm$

Inner diameter =6cm ➡ Inner radius,

$r = \frac{6}{2} = 3cm$

Volume of the copper used in making the pipe

$\large\red{ = \pi {R}^{2}h - {\pi}r^{2}h }$

$\large\red{\pi\:h( {R}^{2} - {r}^{2}) = \frac{22}{7} \times 210 \times [(5)^{2} - (3)^{2}]}$

$\</strong><strong>s</strong><strong>m</strong><strong>a</strong><strong>l</strong><strong>l</strong><strong>\red{22 \times 30 \times (25 - 9) = 660 \times 16 = 10560cm^{3}. }$

${\</strong><strong>l</strong><strong>a</strong><strong>r</strong><strong>g</strong><strong>e</strong><strong>{\underline{\underline{\sf{\</strong><strong>g</strong><strong>r</strong><strong>e</strong><strong>e</strong><strong>n</strong><strong>{</strong><strong>H</strong><strong>e</strong><strong>n</strong><strong>c</strong><strong>e</strong><strong>,</strong><strong>}}}}}}$

Volume of the copper used in making the pipe is

$\large\pink{ = 10560 {cm}^{3} }$

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