Multiple choice

If ratio of the radius and height of a cylinder is $3:2$, and radius $=21$ cm, then total surface area is

  1. $4620$  $ cm^{2}$
  2. $4000$   $cm^{2}$
  3. $4260$    $cm^{2}$
  4. $6240$   $cm^{2}$
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A Correct answer
Explanation

Given r:h = 3:2 and r = 21, then h = 14. Total surface area = 2 * pi * r * (r + h). Using pi = 22/7, Area = 2 * (22/7) * 21 * (21 + 14) = 2 * 22 * 3 * 35 = 4620 cm^2.

AI explanation

Given the ratio of radius to height is 3:2 and the radius is 21 cm, the height is calculated as (2/3)21, which equals 14 cm. The total surface area of a cylinder is found using the formula 2*pi*r(r+h). Substituting the values gives 2 * (22/7) * 21 * (21 + 14), which simplifies to 132 * 35, resulting in 4620 cm^2.

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