Question

The curved surface area of a cylindrical pillar is 220m and its volume is 385m. Find the
diameter and the height of the pillar.​

Answer 1

Answer:

The curved surface area of a cylinder (CSA) = $220 {m}^{2}$

The volume of the cylinder = $385 {m}^{3}$

To be found :-

the diametre and the height of the cylinder

CSA = 2πrh

= 220 = 2 × 22/7 × rh

= 220 = 44/7 × rh

= 220 × 7/44 = rh

= 35 = rh

Now,

Volume = $\pi {r}^{2} h$

$= 385 = 22 \div 7 \times r \times r \times h$

$= 385 = 22 \div 7 \times r \times rh$

$= 385 = 22 \div 7 \times 35 \: (as \: we \: got \: rh = 35)$

$= 385 = 110 \times r$

$= 385 \div 110 = r$

$= 3.9 = r$

Now,

$rh = 35$

$= 3.5 \times h = 35$

$= h = 35 \div 3.5$

$= h = 10$

Therefore,

Diameter = 2r = 2 × 3.5 = 7m

Height = 10 cm

Hope this help you

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