Inner diameter of circular well, d = 3.5 m.
Radius, r = \(\frac{3.5}{2}\)m
Depth of the well – height, h = 10 m.
(i) Inner surfacer area of circular well, C.S.A. = 2πrh
C.S.A. = 2πrh
= 22 × 0.5 × 10 = 110 m2
(ii) Cost of plastering of area 1 m2 is Rs. 40 Cost of plastering 110 m2… ? …
= 110 × 40
= Rs. 4400.