The inner diameter of a circular well is 3.5 m. It is 10 m deep. Find
(i) its inner curved surface area,
(ii) the cost of plastering this curved surface at the rate of rs 40 / m2
Radius of circular well (r) = 3.5/2 m = 1.75 m
Depth of the well (h) = 10 m
Rate of plastering = rs 40 per m2
(i) Curved surface = 2πrh
= (2 × 22/7 × 1.75 × 10) m2
= 110 m2
(ii) Cost of plastering = ���(110 × 40) = rs4400
