How many cubic metres of earth must be dogout to sink a well 21m deep and 6m diameter? Find the cost of plastering the inner surface of the well of Rs. `9. 50\ p e r\ m^2dot`

Explanation

Height, `h=21m` and diameter, `d=6m`

So, radius, `r=6/2=3m`

Plastering rate = Rs.9.50 per `m^2`

Volume of plastering, `V=pir^2h`

`V=22/7xx(6/2)^2xx21`

`V=594m^3`

C.S.A of plastering the inner surface of the well = `2pirh`

`C.S.A=2xx22/7xx3xx21`

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