Here, r = 3. 5/ 2 m , h = 10 m
(i) Inner curved surface area of the well
= 2πrh = 2 × 22/ 7 × 3. 5 /2 × 10m2
= 22 × 5 m2 = 110 m2 Ans.
(ii) Cost of plastering 1 m2 = Rs 40
∴ Cost of plastering the curved surface area of the well
= Rs 110 × 40 = Rs 4400 Ans