Question

please give me answer fast

Answer 1

CSA curved surface area of the roller = 2π.r.h

= 2π x 21/2 x 40

= 2640 cm²

Takes 300 revolutions

So area of the room = 300 * 2640

= 792000 cm²

To convert it to m² we need to divide by 10000

= 792000/10000

= 79.2 m² is the area of the floor.

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(2) Diameter = 56

Radius = 56/2 = 28 cm = 0.28 m

Height = 2.25 m

Total surface area of metallic cylinder = 2.π.r.(r+h) 

= 2 * 22/7 * 0.28 * (0.28+2.25) 

= 2 * 22/7 * 0.28 * 2.53 

= 4.4528 m² 

Cost per sq m = 80

So, total cost = 4.4528 × 80 

= 356.224