Multiple choice

Find the curved surface area of frustum cone radii 3 and 9 cm and a slant height 12 cm.

  1. 144 $\pi cm^2$
  2. 134 $\pi cm^3$
  3. 124 $\pi cm^3$
  4. 114 $\pi cm^3$
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A Correct answer
Explanation

The curved surface area of a frustum is pi * (r1 + r2) * l. Here r1=3, r2=9, l=12. Area = pi * (3+9) * 12 = pi * 12 * 12 = 144 * pi.

AI explanation

The curved surface area of a frustum of a cone is calculated as CSA = pi * (R + r) * l, where R and r are the bottom and top radii and l is the slant height. Plugging in the given values results in CSA = pi * (9 + 3) * 12. This evaluates to 144*pi cm^2.

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