Question

30 Circular Plates, each of Radius 14 cm and Thickness 3 cm are placed one above the another to form a Cylinder Solid. Find

(i) The Total Surface Area.
(ii) Volume of the Cylinder so formed.

Answer 1

Solution :-

Given,

Radius of a Circular Plate, r = 14 cm

Thickness of the Circular Plate = 3 cm

∴ Thickness of 30 Circular Plates = $30 \times 3 = \bold {90\: cm}$

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30 Circular Plates are placed one above another to form a Cylinder Solid. Then,

(i) Total Surface Area = $\bold {[2\pi r\: (r + h)]}$

$2 \times \frac{22}{7} \times 14\: (14 + 90)\\\\\Rightarrow 44 \times 2 \times 104 \\\\= \bold {9,152\: cm^2}$

Hence,

The Total Surface Area of the Cylinder Solid is $\bold {9,152\: cm^2}$.

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(ii) Volume of the Cylinder so formed = $\bold {\pi r^2h}$

$\frac{22}{7} (14)^2 \times 90 = \frac{22}{7} \times 14 \times 14 \times 90\\\\\Rightarrow 22 \times 28 \times 90\\\\= \bold {55,440\: cm^3}$

Hence,

The Volume of the Cylinder so formed is $\bold {55,440\: cm^3}$.

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