Question

SECTION - D
(4*6=24)
35. How many cubic metres of earth must be dug out to sink a well 22.5 m deep and of diameter
7 m. Also find the cost of plastering the inner curved surface at 3 per square metre.​

Answer 1

Answer:

volume of earth dug out=866.25m^3

cost of plastering= 1485rs

Step-by-step explanation:

volume of earth dug out=

$\pi {r}^{2} h$

=22/7*7/2*22.5 [radius=d/2]

=1732.5/2

=1732.5*10/2*10

=17325/20

=866.25m^3

curved surface area =

$2\pi \: rh$

=2*22/7*7/2*22.5

=495m^2

cost of plastering=curved surface area*cost of plastering per metre sq

=495*3

=1485rs