What is the volume of the frustum?
Consider the following for the next two (02) items that follow :<br>A frustum of a right cone has a top of diameter 2k, bottom of diameter 2.5k and height k.
- A. 61\pi k^{3}/48 ✓
- B. 59\pi k^{3}/48
- C. 57\pi k^{3}/48
- D. 53\pi k^{3}/48
Correct Answer: A. 61\pi k^{3}/48
Explanation
Volume of a frustum is V = \frac{1}{3}\pi h (R^2 + r^2 + Rr). Here h=k, r=k, R=1.25k=\frac{5}{4}k. So V = \frac{1}{3}\pi k (\frac{25}{16}k^2 + k^2 + \frac{5}{4}k^2) = \frac{1}{3}\pi k^3 (\frac{25+16+20}{16}) = \frac{61\pi k^3}{48}.
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