Question

The diameter of a roller is 84 cm and its length is 120 cm. It takes 500 complete revolutions moving monce over to level a playground. What is the area of the playground?

Answer 1

Given,

Diameter of roller = 84 cm

Radius of roller = \(\frac{84}{2}\) = 42 cm

Length of roller = 120 cm

So,

Curved surface area of roller = 2πrh = 2 x \(\frac{22}{7}\) x 42 x 120 = 31680 cm²

No. of revolution it takes to level the ground = 500 given

Hence,

Area of play ground = 500 × 31680 = 15840000 cm² = 1584 m²