Question

A metal pipe is 77 cm long.The inner diameter of a cross section is 4 cm the outer diameter being 4.4 cm find it's
(I) Inner curved surface area.
(ii) Outer curved surface area.
(iii) Total surface area.​

Answer 1

$\huge\boxed{\fcolorbox{white}{pink}{Answer}}$

see in attachment.. okay dude

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Answer 2

$\bf{\underline{\purple{Question:-}}}$

✓✓A metal pipe is 77cm long.The inner diameter of a cross section is 4 cm and the outer diameter being 4.4 cm find it's :-

• (i) Inner curved surface area.
• (ii) outer curved surface area.
• (iii) Total surface area.

$\bf{\underline{\green{Solution:-}}}$

$\bf\boxed\star\pink{\underline{\underline{{(i)\:Inner\: Curved\: Surface\:area}}}}$

$\bf\:Given,$

• $\bf\: Diameter=4\:cm$

• $\bf\:radius=\dfrac{Diameter}{2}$

• $\bf\:radius=\dfrac{4}{2}=2\:cm$

• $\bf\: height=77\:cm$

$\bf\:Inner\:C.\:S.\:A=2πrh$

$\bf\:Inner\:C.\:S.\:A=2\times\dfrac{22}{7}\times\:2\times\:77\:c{m}^{2}$

$\bf\:Inner\:C.\:S.\:A=2\times\:22\times\:2\times\:11\:c{m}^{2}$

$\bf\:Inner\:C.\:S.\:A=968\:c{m}^{2}$

$\bf\boxed\star\orange{\underline{\underline{{(ii)\:Outer\: Curved\: Surface\:area}}}}$

$\bf\:Given,$

• $\bf\: Diameter=4.4\:cm$

• $\bf\:radius=\dfrac{Diameter}{2}$

• $\bf\:radius=\dfrac{4.4}{2}=2.2\:cm$

• $\bf\: height=77\:cm$

$\bf\:Outer\:C.\:S.\:A=2πrh$

$\bf\:Outer\:C.\:S.\:A=2\times\dfrac{22}{7}\times\:2.2\times\:77\:c{m}^{2}$

$\bf\:Outer\:C.\:S.\:A=2\times\:22\times\:2.2\times\:11\:c{m}^{2}$

$\bf\:Outer\:C.\:S.\:A=1064.80\:c{m}^{2}$

$\bf\boxed\star\blue{\underline{\underline{{(iii)\:Total\: Surface\:area}}}}$

$\bf\: Given,$

• $\bf\:R=2.2\:cm$

• $\bf\:r=2\:cm$

• $\bf\:h=77\:cm$

$\bf\:Area\:of\:upper\:ring= π({R}^{2}-{r}^{2})$

$\bf\: Area\:of\:upper\:ring=\dfrac{22}{7}\times\:{(2.2)}^{2}-{(2)}^{2}\:c{m}^{2}$

$\bf\: Area\:of\:upper\:ring=\dfrac{22}{7}\times\:4.84-4\:c{m}^{2}$

$\bf\: Area\:of\:upper\:ring=22\times\:0.12\:c{m}^{2}$

$\bf\: Area\:of\:upper\:ring=2.64\:c{m}^{2}$

$\bf\: Area\:of\:lower\:ring=2.64\:c{m}^{2}$

$\bf\:T.S.A=Inner\:C.S.A+Outer\:C.S.A+Area\:of\:lower\:ring+Area\:of\:upper\:ring$

$\bf\:T.S.A= 968+1064.80+2.64+2.64$

$\bf\:T.S.A=2038.08\:c{m}^{2}$