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प्रश्न
30 circular plates, each of radius 14 cm and thickness 3 cm are placed one above the another to form a cylindrical solid. Find the total surface area.
उत्तर
Given, radius of a circular plate, r = 14 cm
Thickness of a circular plate = 3 cm
Thickness of 30 circular plates = 30 × 3 = 90 cm
Since, 30 circular plates are placed one above the another to form a cylindrical solid.
Then, Height of the cylindrical solid, h = Thickness of 30 circular plates = 90 cm
Total surface area of the cylindrical solid so formed
= `2πr(h + r) = 2 xx (22/7) xx 14(90 + 14)`
= 44 × 2 × 104
= 9152 cm2
Hence, the total surface area of the cylindrical solid is 9152 cm2.
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