Question

The diameter of a roller is 84 cm and its length is 120 cm. It takes 500 complete revolutions to move once over to level a playground. Find the area of the playground in m2? (Assume π = 22/7)​

Answer 1

Answer:

Step-by-step explanation:

Radius of the roller (r)= 84/2  =42cm

length of the roller (h)=120cm

∴ Area of the playground levelled in taking 1 complete revolution 2πrh

=2×227×42×120=31680cm2  

∴ Area of the playground

=31680×500=15840000cm2  

Answer 2

Given:-

• d = 84 cm
• r = 21/50 m
• h = 42/100 m = 21/50 m

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To Find:-

• Area of playground

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Solution:-

★ Using Formula

$\boxed{ \pink{ \sf \: Curved \: surface \: area \: of \: cylinder =2πrh}}$

$\sf \implies \: 2 \times \frac{22}{7} \times \frac{21}{50} \times \frac{6}{5}$

$\sf \implies \frac{66 \times 6}{125} {m}^{2}$

$\sf \implies \frac{396}{125} \: {m}^{2}$

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★ Revolution 500 times

$\sf \implies \frac{396}{125} \times 500$

$\sf \implies 1584 \: {m}^{2}$

Therefore, area of playground is 1584 m².