Multiple choice

The curved surface of a cylinder is $\displaystyle 1000{ \ mm }^{ 2 }$ and the radius is $20$ mm. Find height of the cylinder. (Round off the answer to nearest whole number).

  1. $\displaystyle 8{\  mm }$
  2. $\displaystyle 9{\  mm }$
  3. $\displaystyle 7.9{\  mm }$
  4. $\displaystyle 7.96{\  mm }$
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A Correct answer
Explanation

Curved surface area of a cylinder = 2 * pi * r * h. 1000 = 2 * 3.14159 * 20 * h. 1000 = 125.66 * h. h = 1000 / 125.66 = 7.958. Rounding to the nearest whole number gives 8.

AI explanation

The curved surface area of a cylinder is calculated as 2 times pi times r times h. Substituting the given values, 1000 equals 2 times 3.14 times 20 times h, which simplifies to 1000 equals 125.6 times h. Solving for h gives approximately 7.96 mm, which rounds to 8 mm.

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