Question

"Question 7 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 per m^2 .

Class 9 - Math - Surface Areas and Volumes Page 217"

Answer 1

See the attachment....

Hope it help⛎⛎⛎

Answer 2

Heya

Here is your answer .

========================================================================

( i ) 2r = 3.5 meter

=> r = 3.5/2 meter

=> r = 1.75 meter

h = 10 meter

.°. Inner curved surface area = 2πrh

= 2 × 22/7 × 1.75 × 10

= 110 meter²

( ii ) The cost of plastering this curved surface at the rate of Rs. 40 per meter² =

110 × 40

= 4400 Rupes.

========================================================================