Question

the outer diameter of metallic pipe is 18cm and the thickness of pipe is 2cm and the height is 4cm. find the surface area of the metallic pipe​

Answer 1

Given,

• Outer diameter = 18 cm
• Thickness = 2 cm
• Height = 4 cm

To find :-

The surface area of metallic pipe.

Solution :-

Given,

Outer diameter = 18 cm

$\large \rm Radius ( R ) \: outer \: radius = \frac {d}{2} \\ \implies \large \rm \frac {\cancel{18}\: \: ^{9}}{\cancel2}\\ \\ \large \rm \therefore R = 9 cm$

Thickness = 2 cm

The inner radius = 9 - 2 = 7 cm

Height of the pipe = 4 cm

$\sf\underline\blue{ The \: metallic \: pipe \: has \: the \: shape \: of \: cylinder }$

Surface area of outer pipe = $\rm 2 \pi Rh$

$\implies \: 2\pi \times 9 \times 4$

$\bf \: outer \: area = 72\pi {cm}^{2}$

Inner surface area of pipe = $\rm 2 \pi rh$

$\implies\rm \: 2 \times \pi \times 7 \times 4$

$= \bf \: 56\pi {cm}^{2}$

Now,

The surface area of metallic pipe = 2πRh - 2πrh

$\implies \bf \: 72\pi - 56\pi \\ \bf \implies \: Area = 16\pi{cm}^{2}$

Henceforth,

$\sf \blue{The \: surface \: area \: of \:metallic \: pipe \: = 16\pi {cm}^{2} }$

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$\large\fbox \red {Hope \: it \: helps \: you}$