The inner diameter of a circular well is 3.5 m. It is 10 m deep Find:
(i) inner curved surface area.
(ii) the cost of plastering this curved surface at the rate of Rs. 40 per m2.
Given,
Inner diameter of circular well = 3.5 m
Inner radius = 
Depth of well = 10 m
i) Inner curved surface area of well = 2πrh = 
m2
ii) Cost of plastering 1m2 area = Rs.40
Cost of plastering 110 m2 = 40×110 = 4400 rs.
10