Question

diameter and length of a roller are 84 cm and 120 CM respectively in how many Revolution can the roller level the playground of area 1584 m square

Answer 1

Solution -

We know, that the roller is in the form of a cylinder.

Radius = d/2 = 84/2 cm = 42 cm

∵ Curved Surface Area of roller = 2πrh

= [ 2 × 22/7 × 42 × 120 ] cm²

= [ 2 × 22 × 6 × 120 ] cm²

= 31,680 cm²

= 3.168 m²

We know,

Area of playground = 1584 m²

∴ No. of revolutions

= Area of playground / Curved surface Area of cylinder

= 1584 m²/3.168 m²

= 500

∴ The roller will take 500 revolutions

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