Question

The inner diameter of well is 3.5 cm. It is 10m deep. Find :


1) Inner Curved surface area


2) The cost of painting @Rs 40 per m^2

Answer 1

$\huge\bf\purple{QUESTION:-}$



The inner diameter of well is 3.5 cm. It is 10m deep. Find :

1) Inner Curved surface area

2) The cost of painting @Rs 40 per m^2




$\huge\bf\red{ANSWER:-}$




Radius of circular well=1/2×3.5= 7/4 m

1) Inner Curved surface area= 2πrh= 2×22/7×7/4×10

$= 110 \: m {}^{2}$

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2) As the cost of painting the surface= Rs 40 per m^2

Therefore,

The cost of painting the curved surface area= Rs(110×40)= Rs 4400

Answer 2

Diameter = 3.5 cm

Height =10m = 100cm

Now , formula for finding Curved Surface Area = π2rh

=22/7×3.5×100

=22/7×350

=22×50

=1100 cm*2

Now ,cost of painting per m*2 = Rs 40

cost of painting 11m*2=Rs 11×40

=Rs 440