Question

The diameter of a roller is 42 cm and its length is 60 cm. It takes 1000 complete revolution to move once over to level a playground. Find the area of the playground in m2​

Answer 1

Answer:

Radius of the roller (r)=

2

84

cm=42cm

length of the roller (h)=120cm

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

=2×227×42×120=31680cm

2

∴ Area of the playground

=31680×500=15840000cm

2

100×100

15840000

m

2

=1584m

2

Answer 2

Answer:

• 729 m² is the required area of playground

Step-by-step explanation:

According to the Question

It is given that,

• Diameter of roller ,d = 42 cm
• Length ,h= 60cm
• No. of revolution = 1000

we have to calculate the area of playground .

Calculating the Radius of roller

→ Radius = d/2

→ Radius = 42/2

→ Radius = 21 cm

Area of Playground in 1 Revolution = 2πrh

substituting the value we get

→ Area in 1 Revolution = 2×22/7×21×60

→ Area in 1 Revolution = 44 × 3 × 60

→ Area in 1 Revolution = 7920 cm²

So, Area in 1000 Revolution = 7920×1000

→ Area in 1000 Revolution = 7920000 cm²

Conversion of Unit

Area in1000 Revolution =7920000/10000

→ Area in 1000 Revolution = 792 m²

• Hence, the area of playground is 792 m².