Question

16) 50 circular plates each of radius 7 cm and thickness 0.5 cm are placed one above the other to form a
solid right circular cylinder. What is the total surface of the cylinder?
(A) 1208 cm2 (6) 1390 cm? c) 1408 cm2 (D) 1478 cm?
(E) None of this​

Answer 1

A=2πrh +2πr^2

=2·π·0.07·0.25+2·π·0.07^2

≈0.14074

so ans is c

Answer 2

Thanks for asking :)

Answer :

Option C

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Explanation

Since the radius of the cylinder is same as the radius of the circular plate.

So, the radius of the base of the cylinder = 7 cm

Height of the cylinder is same as the thickness of 50 circular plates.

Thickness of 1 plate = 1/2 cm

Then,

thickness of 50 plates = 50*1/2

= 25 cm

Height of the cylinder = 25 cm

Total surface area of cylinder = 2πr(r+h)

= 2*22/7*7(7+25)

= 44*32

Total surface area of the cylinder = 1408 sq cm

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