Question

In a building there are 24 cylindrical pillars. The diameter of each pillar is 56 cm and height is 10 m. Find the total cost of painting the curved surface area of all pillars at the rate of ₹ 10 per sq m.

Answer 1

Answer:

4224 Rs

Step-by-step explanation:

What to do?

first of all, only the lateral surface area would be painted,

so we'll have to find the lateral surface area of the cylinder and then multiply it by 24 to find the whole LSA and finds its cost by again multiplying by 10.

Finding LSA:

first let's find the radius,

Radius = D/2 = 56/100*1/2= 0.28m

LSA of cylinder = 2πrh

= 2 * 22/7 * 28/100 * 10

= 88/5 m²

Finding LSA of all the pillars:

LSA of all pillars = 88/5 * 24

= 2112/5 m²

Finding the cost:

cost of painting = 2112/5 * 10 = 4224 Rs.

Answer is 4224 Rs

Sple as that.

Answer 2

Step-by-step explanation:

first we have to find the radius,

$\sf \: Radius = \frac{D}{2} = \frac{56}{100} \times \frac{1}{2} =0.28m$

$\sf \: LSA \: of \: cylinder = 2 \pi r h \\ \:sf=2 \times \frac{22}{7} \times \frac{28}{100} \times 10 \\ \sf= \frac{88}{5} m^ 2$

Now we have to find LSA of all the pillars:

$\sf \: LSA of aII pillars= \frac{88}{5} \times 24 \\ \sf = \frac{2112}{5} m^ 2$

Now ,

Finding the cost:

$\sf \: cost \: of \: painting= \frac{2112}{5} \times 10 \\ \sf=4224 Rs.$

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Hope it helps you army :-)

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I am Mansi

Class 8

From Uttarakhand

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