Multiple choice

The radius of base and the height of a right circular cylinder are each increased by 20%. The volume of the cylinder will increase by

  1. 72.8%

  2. 96%

  3. 40%

  4. 60%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Volume V = pi * r^2 * h. If r and h increase by 20%, the new volume V' = pi * (1.2r)^2 * (1.2h) = pi * 1.44r^2 * 1.2h = 1.728 * V. The increase is 72.8%.

AI explanation

Using successive percentage increases for volume, the net percentage change is calculated as x + y + (xy/100). Applying the 20% increases for both radius and height gives 20 + 20 + (20 * 20 / 100), which equals 44% for the squared radius term plus 20% for the height, resulting in a combined effective increase of 72.8%.

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