Choose the correct answer of the following question:
A rectangular sheet of paper 40 cm
(a) 3.5 (b) 7 (c) 80 (d) 5
We have,
Length of the rectangular sheet, $l=40 \mathrm{~cm}$,
Width of the rectangular sheet, $b=22 \mathrm{~cm}$ and
Height of the hollow cylinder, $h=40 \mathrm{~cm}$
Let the radius of the cylinder be $r$.
As, $l=h$
So, the circumference of base of the cylinder $=b$
$\Rightarrow 2 \pi r=22$
$\Rightarrow 2 \times \frac{22}{7} \times r=22$
$\Rightarrow r=\frac{22 \times 7}{2 \times 22}$
$\therefore r=3.5 \mathrm{~cm}$
Hence, the correct answer is option (a).
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