Question

The length of a roller is 440cm and its diameter is 21cm.It takes 300 revolution to move once over to level the floor of a room.Find the area of the room in sq.m

Answer 1

curved surface area of cylinder = 2 pie rh
=2×22/7×10.5×440
=29040cm^2
29.04 m^2
it's revolve once over the floor 300
29.04 ×300
8712

Answer 2

Given
D=21cm
R=21/2cm
L or h=440cm

The curved surface area roller =
$2\pi \: rh \:$
=
$\frac{2 \times 22 \times 21 \times 440}{7 \times 2}$
=29040cm²
In one revolution area cover or moved=29040cm²

In 300 revolution =300x29040
=8712000cm²

In meters =871.2m²

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