Question

1)The dimensions of a roller is 2.5m and length is 1.5m and it's length is 1.4m. How much area will it cover in 7 revolutions?

2) Radius of the base of a right circular cylinder is 14 dm and height is 15m. Find the
i. CSA of the cylinder
ii. TSA of the cylinder.

Answer 1

Hello..
Answer.

1)
$radius \: of \: the \: roller \: (cylinder) = \frac{2.5}{2} m \\ length \: of \: the \: roller \: = 1.4m \\ curved \: surface \: area \: of \: the \: area \: of \: the \: roller = 2\pi \: r \: h \\ = 2 \times \frac{22}{7} \times \frac{2.5}{2} = 11 {m}^{2} \\ \\ we \: know \: that \: \\ area \: covered \: in \: one \: revolution \: = curved \: surface \: area \: of \: the \: roller \\ therefore.. \\ area \: covered \: in \: 7 \: revolutions \: = 7 \times curved \: surface \: area \\ = 7 \times 11 = 77 {m}^{2}$


2) Solution

$here \\ r = 14dm = \frac{14}{10}m = 1.4m \\ h = 15m \\ \\ curved \: surface \: area \: of \: the \: cylinder = 2\pi \: r \: h \\ = 2 \times \frac{22}{7} \times \frac{14}{10} \times 15 \\ = 132 \\ \\ total \: surface \: area \: of \: the \: cylinder \: \\ = 2\pi r\:( r \: h) \\ = 2 \times \frac{22}{7} \times 1.4(1.4 + 15) \\ = 2 \times 22 \times 0.2(16.4) \\ 144.32 {m}^{2}$

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Answer 2

Here is the answer in the pic....


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