Mathematics
If the volume of a cylinder of height 7 cm is 448 π cm3, find its lateral surface area and total surface area.
Mensuration
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Answer
Volume of cylinder = πr2h.
Given, Volume of cylinder = 448 π cm3 and height = 7 cm.
∴ πr2h = 448 π
⇒ r2h = 448 (Dividing both sides by π)
⇒ r2 × 7 = 448
⇒ r2 =
⇒ r2 = 64
⇒ r = = 8 cm.
Lateral surface area of cylinder = 2πrh = 2π × 8 × 7 = 112π cm2.
Total surface area = 2πr(h + r) = 2π × 8 × (8 + 7) = 2π × 8 × 15 = 240π cm2.
Hence, the lateral surface area of cylinder = 112π cm2 and total surface area = 240π cm2.
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