Question

30 circular plates, each of radius 14 cm and thickness 3cm are placed one above the another to form a cylindrical solid. find : (i) the total surface area

Answer 1

thickness of 1 plate =3 CM
thickness of total 30 plates =90 cm
so height of cylinder =90 CM
and radius =14 CM
Now
total surface area of cylinder
$= 2\pi \: r \: (h + r) \\ = 2\pi(14)(44) \\ = 2(22 \div 7)(14)(44) \\ = 2 \times 22 \times 2 \times 44 \: {cm}^{2}$
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Answer 2

Answer:

Step-by-step explanation:

Height of the cylinder formed = 3 × 30 = 90 cm

radius = 14 cm

Total Surface Area = 2πrh + 2πr²

= 2π × 14 × 90 + 2π × (14)²

= 7920 + 1232 = 9152 cm²

Volume = πr²h = π × (14)² × 90

= 55440 cm³