Question

1. The diameter of a roller is 2.5 m and it's length is 1.4 m. How much area will it cover in 7 revolutions?
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Answer 1

Answer:

roller will cover 10.99m2 (when π=3.14)

Step-by-step explanation:

area covered in one revolution = curved surface area of the roller

=2πrh

=2π*(2.5/2)*1.4

=2π*1.25*1.4

=2π*1.75

=6.28*1.75

=10.99m2

area covered in 7 revolution =7*10.99

=76.93m2

Answer 2

$\huge{\bigstar{\underline{\red{\mathfrak{Solution}}}}}$

$\sf{Radius\: of \:the\: roller = \frac{2.5}{2} m}$

$\sf{Length \:of \:the\: roller = 1.4m}$

$\sf{Curved\: surface\: of \:area \:of\: the\: roller = 2πrh}$

$\sf{ 2 \times \frac{22}{7} \times \frac{2.5}{1.4} = {11m}^{2} }$

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$\tt{We \:know \:that-}$

Area covered in one revolution = Curved surface area of roller

$\tt{Therefore,}$

Area covered in 7 revolutions

$\tt{= 7 \times curved \:surface\: area}$

$\tt{7 \times 11 = {77m}^{2}}$