Question

how many cubic metre of earth must be dug out to sink avail 22.5 m deep and diameter 7m? Also, find the cost of plastering it at ₹3 per sq m.
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Answer 1

Step-by-step explanation:

$h = 22.5m \\ r = \frac{d}{2} \\ = \frac{7}{2} \\ = 3.5m \\ volume \: of \: cylinder \: = \: \pi {r}^{2}h \\ = \frac{22}{7} \times 3.5 \times 3.5 \times 22.5 \\ = 866.25 \\ cost \: of \: plastering \: = 3per {m}^{3} \\ = 866.25 \times 3 \\ = 2598.75 {m}^{3}$

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