Question

Road roller of diameter 140 cm and length 2 metre levels 4400m2 of a road. Find the number of revolutions taken by it to cover the given area.

Answer 1

Answer:

Dimensions:

Diameter = 140 cm

Radius = d/2 = 70 cm = 0.7 m

Length = 2 m

Area of road covered in one revolution = $\tt{\pi r^{2}}$

= 22/7 × 0.7 × 0.7 × 2

=> 3.08 sq m

Area of road covered = 4400 sq m

Let the number of revolutions be = n

=> 3.08 × n = 4400

=> n = 4400/3.08

=> n = 1428.5

Round it to the nearest number: 1429 revolutions

_________________

Answer 2

Answer: 1429 revolutions.

Step by step explanation:

Given:

Diameter = 140 cm

.°. Radius = 70 cm = 0.7 m

Length = 2 metres

To find: number of revolutions taken by it to cover the given area.

Solution:

Area of road covered in one revolution = πr²

=> 22/7 × 0.7 × 0.7 × 2

=> 3.08 m²

Area of road covered = 4400 m² ( Given )

Thus, the number of revolutions

= 3.08 × number of revolutions = 4400

= 4400/3.08

= 1428.5

= 1429 revolutions (approx.)

Thus, the number of revolutions taken by it to cover the given area is 1429 approximately.