Question

16. A cylindrical well is 21m deep. Its inner diameter is 14m. Find the

cost of renovating the inner curved surface and the base at the rate of

₹25 per square metre. ​

Answer 1

Answer:

₹23100

Step-by-step explanation:

Inner curved surface area

= 2 × 22/7 × inner radius × height

= 2 × 22/7 × 14/2 m × 21 m

= 2×22×7×3 m^2

= 924 m^2

Total cost = ₹ (924×25) = ₹23100

Hope this helps you.

Answer 2

Answer:

Step-by-step explanation:

Height of the cylinder, h=21 m

Inner radius of the cylinder, r= d/2 = 7m

CSA = 2 π r h

CSA = 2 x 22/7 x 7 x 21

       ⇒ 2 x 22 x 21  

       ⇒ 42 x 22

       ⇒ 924 m²

Cost per meter sq. = ₹25

Cost = 25 x 924

∴ the cost per m² ⇒ ₹ 23,100