Q8 of 18 Page 13

50 circular plates, each of radius 7 cm and thickness  cm, are placed one above another to form a solid right circular cylinder. Find the total surface area and the volume of the cylinder so formed.

Volume of the circular plate = π r2h = × 7 × 7 × = 77 cm3
Volume of the cylinder so formed by 50 circular plate = 50 × 77 = 3850 cm3
Total surface area of the cylinder = 2πr(r + h) = 2 × × 7(7 + 25) = 1408 cm2.

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