Multiple choice

A solid in shape of a frustum is 21 cm high. Its radius of top is 10 cm and diameter of bottom is 30 cm. The volume of the solid is

  1. 10500 $\displaystyle cm^{3}$
  2. 10450 $\displaystyle cm^{3}$
  3. 10000 $\displaystyle cm^{3}$

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Volume of frustum = (1/3) * pi * h * (R^2 + r^2 + R*r). R=15, r=10, h=21. V = (1/3) * (22/7) * 21 * (225 + 100 + 150) = 22 * 475 = 10450.

AI explanation

Using the frustum volume formula V = (1/3) * pi * h * (r1^2 + r2^2 + r1*r2), we identify the height as 21 cm, the top radius as 10 cm, and the bottom radius as 15 cm. Substituting these values gives V = (1/3) * (22/7) * 21 * (100 + 225 + 150). This simplifies to 22 * 475, which equals 10450 cubic cm.

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