Question

Question 7
The inner diameter of a circular well is 3.5 m. It is 10m deep. Find
(i) Its inner curved surface area,
(ii) The cost of plastering this curved surface at the rate of $Rs.40per{m}^2.[Assume\pi =\frac{22}{7}]$

Answer 1

Inner radius (r) of the circular well $=\left(\frac{3.5}{2}\right)m=1.75m$
Depth (h) of the circular well = 10 m
Inner curved surface area $=2\pi rh$
$=(2\times \frac{22}{7}\times 1.75\times 10)m^2=110m^2$
Therefore, the inner curved surface area of the circular well is $110m^2$.
Cost of plastering $1m^{2}area=Rs.40$
Cost of plastering $110m^{2}area=Rs.(110\times 40)$
= Rs. 4400