Question

It is required to make a closed cylindrical tank of height 1m and base diameter 140cm from a metal sheet. How many square metres of the sheet are required for the same.

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Answer 1

$\sf\small{ \underline{\underline{ \pmb{Given:-}}}}$

• h = 1 m
• d = 140 cm
• r = 140/2×100 = 7/10 m

$\sf\small{ \underline{\underline{ \pmb{To \: Find:-}}}}$

• Total surface area

$\sf\small{ \underline{\underline{ \pmb{Formula:-}}}}$

★ Formula that we use

• $\boxed{ \red{ \sf \: Total \: surface \: area=2πr(r+h) }}$

$\sf\small{ \underline{\underline{ \pmb{Solution:-}}}}$

$\sf \: Total \: surface \: area=2πr(r+h)$

$\sf \implies 2 \times \frac{22}{7} \times \frac{7}{10} ( \frac{7}{10} + 1)$

$\sf \implies 2 \times \frac{22}{7} \times \frac{7}{10} \times ( \frac{7 + 10}{10} )$

$\sf \implies 2 \times \frac{22}{7} \times \frac{7}{10} \times \frac{17}{10}$

$\sf \implies \frac{11 \times 17}{5 \times 5}$

$\sf \implies \frac{187}{25}$

$\sf \implies \red{ 7.48 \: {cm}^{2} }$