Question

The inner diagram of a circular well is 3.5m and it is 12m deep. Find the cost of plastering the inner surface at the rate of rupees 4per m^2

Answer 1

given :-

inner diameter of the well = 3.5m

➡ it's inner radius = 3.5/2 m

height (depth) of the well = 12m

therefore inner CSA of the well = 2πrh (since Wells are cylindrical)

= 2 × 22/7 × 3.5 × 12

= 22 × 12

= 264m²

hence, cost of plastering it @ of 4 per m² = 264 × 4

= rupees 1056

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