Question
A solid cylinder has the total surface area 231 sq.cm.
If its curved surface area is of the total surface area, then the volume of the cylinder isSolution
Total surface area = 231 cm2 Curved surface area = 2/3 x 231 = 154 cm2 Curved surface area of cylinder = 2πrh ⇒ 2πrh = 154 ⇒ 2 × (22/7) × r × h = 154 ⇒ r × l = 24.5 Total surface area of cylinder = 2πr(r + h) ⇒ 2πr(r + h) = 231 ⇒ r(r + h) = 36.75 ⇒ r2 + rh = 36.75 ⇒ r2 = 36.75 - 24.5 ⇒ r2 = 12.25 ⇒ r = 3.5 cm Volume of cylinder = πr2h ⇒ π × r × (r × h) ⇒ π × 3.5 × 24.5 ⇒ 269.5 cm ∴ The volume of the cylinder is 269.5 cm3 .
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16, 24, 36, 54, 81, 120.5
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33Â Â Â Â 34Â Â Â 37Â Â Â 42Â Â Â 48Â Â Â 58
66, 115, 34, 155, 14, 211
360, 322, 286, 248, 220, 190
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7, 35, 42, 126, 128, 118 - Find the wrong number in the given number series.
2, 6, 14, 30, 62, 126 Find the wrong number in the given number series.
134, 163, 194, 231, 274, 315
125, 142, 199, 320, 489, 778
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32, 48, 84, 146, 248, 392