Question

an 18 cm long iron pipe has an external diameter of 24 cm if the thickness of the pipe is 1 cm find the csa of the pipe

Answer 1

csa of cylinder is πr²h

Answer 2

Solution:

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Given:

An 18 cm long iron pipe has an external diameter of 24 cm if the thickness of the pipe is 1 cm.

 ∴ Shape : cylindrical pipe (Hollow cylinder)

=> h = 18 cm,

=> External radius = 24/2 = 12cm

=> Internal radius =  external radius - thickness = 12 - 1 = 11cm,

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To Find:

CSA of the pipe

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As, we know that,

CSA of hollow cylinder = 2π(R+r)h

=> $2 (\frac{22}{7})(12 + 11)(18)$

=> $( \frac{44}{7} )(23)(18)$

=> $\frac{44(414)}{7}$

=> $\frac{18216}{7}$

=> $2602.285714..$ ≈ 2602.3 cm².

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