Question

The curved surface area of a cylindrical road is
${132cm}^{2}$
. Find its length if the radius is 0.35 cm
​

Answer 1

To find length [h or l]

Given:

CSA of cylinder =132cm^2

=

$2\pi \: rh = 132 \\ = > h = \frac{132}{2\pi \: r} \\ = > h = \frac{132}{2 \times 3.14 \times 0.35} \\ = > h = \frac{132}{2.198} \\ = > h = 60.05$

hence the length of the cylindrical road is {60.05} cm

Answer 2

Given that radius of the cylindrical road is equals to 0.35cm.

Also,

Given that its curved surface area is equals to 132 to sq. cm.

As we know that

CSA of cylinder

$CSA = 2 \pi rl$

where r is radius of cylinder and l is length of cylinder.

Here,

ATQ,

$2 \pi rl = 132 \\ 2 \times \dfrac{22}{7} \times 0.35 \times \: l = 132 \\ l = \dfrac{132 \times 7}{2 \times 22 \times 0.35}\\ \\ l = \dfrac{3 \times 7 \times 100}{35} \\ \\ l = \dfrac{2100}{35} \\ \\ l = 60cm$

So, length of cylindrical rod will be 60 cm.