Question

The inner diameter of a circular well is 4.2m. It is 12m deep. Find (1) It's inner curved surface area (2) the cost of plastering the inner curved surface at the rate of &₹ 50 per m square.​

Answer 1

Answer:

37920

Step-by-step explanation:

inner c.s.a = 2πrh

=158.4

cost =158.4*50

37920rs.

Answer 2

Answer:Inner Diameter of the well = 4.2 m 

Radius = 4.2/2 = 2.1 m

Depth or Height of the well = 12 m

Curved Surface Area of cylinder = 2πrh 

⇒ 2*22/7*2.1*12

⇒ 1108.8/7

⇒ 158.4 m²

So, Inner curved surface area of the well is 158.4 m²

cost of plastering = 50 * 158.4

                              = 7920 rupees