Question

a well is dug whose diameter is 4 metre and the depth is 10 metre. Find the quantity of soil taken out. Find the cost of plastering the inner curved surface at Rs.35 per metre square.​

Answer 1

HeY MatE !!

HerE IS YouR AnsweR ——————

Diameter of cylindrical well = $4 \: m$

so, radius of well = $\frac{4}{2} = 2 \: m$

Height of well = $10 \: m$
_________________________________

[To find the quantity of soil which is dug , we need to find the volume first]

therefore,

$volume \: of \: well = \pi {r}^{2} h \\ \\ = \frac{22}{7} \times( 2 \times 2 )\times 10 \\ \\ = \frac{880}{7} \\ \\ = 125.71 \: {m}^{3}$

so, the quantity of soil which is taken out is 125.71 m³
_________________________________

now , for curved surface area —————

$Curved \: surface \: area = 2\pi \: rh \\ \\ = 2 \times \frac{22}{7} \times 2 \times 10 \\ \\ = \frac{880}{7} \: m {}^{2}$

therefore, the curved surface area of well is $\frac{880}{7} \: {m}^{2}$
_________________________________

now, cost of plastering 1 m² of well = ₹35

so, cost of plastering $\frac{880}{7} \: {m}^{2}$of well =

$= \frac{880}{7} \times 35 \\ \\ = 880 \times 5 \\ \\ = 4400 \: rupees$

therefore, cost of plastering the curved surface area of the well is ₹ 4400.
________________________________
✨PLEASE MARK IT AS

BRAINLIEST✨