Multiple choice

The radius and height of a cylinder are in the ratio 5:7 and its volume is 550 cm3. Calculate its curved surface are in sq. cm.

  1. 110

  2. 444

  3. 220

  4. 616
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let radius r = 5k and height h = 7k. Volume V = πr²h = π(5k)²(7k) = 175πk³ = 550 cm³. Solving: k³ = 550/(175π) ≈ 1, so k ≈ 1. Thus r ≈ 5 and h ≈ 7. Curved surface area = 2πrh = 2π(5)(7) = 70π ≈ 220 cm². Using π = 22/7: 70 × 22/7 = 220. Option C is correct.

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