Answer:

[tex]given \\ A \: metallic \: pipe \: has \\ internal \: and \: external \: diameter \: 10 cm \\ and \: 12 CM \: and \: its \: length \: is \: 4.2m

[/tex]

[tex]to \: find \: its \: total \: surface \: area[/tex]

[tex]first \: we \: have \: to \: find \: internal \\ curved \: surface \: area \: and \\ external \: curved \: surface \: area[/tex]

taking π=3.14

length or height of pipe =4.2cm

=4.2×100

=420cm

as all units are in normal cm so we converted

[tex]internal \: curved \: surface \: area = internal \: circumference \times length[/tex]

[tex]by \: substituting \: the \: values \: we \\ get[/tex]

[tex] = \pi \: d \times h[/tex]

[tex] = 3.14 \times 10 \times 420 \\ = 13188 {cm}^{2} [/tex]

[tex]external \: curved \: surface \: area = \pi \: d \times h[/tex]

[tex] = 15825.6 {cm}^{2} [/tex]

[tex]d \: is \: diameter \: and \: h \: is \: height[/tex]

[tex]total \: surface \: area \: of \: pipe = internal \: \\ curved \: surface \: area + external \: curved \: surface \: area[/tex]

[tex]on \: substituting \: the \: values \: we \: get[/tex]

[tex] = 13188 {cm}^{2} + 15825.6 {cm}^{2} [/tex]

[tex] = 29013.6 {cm}^{2} [/tex]

therefore total surface area of pipe is 29013cm^2

Step-by-step explanation:

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