Difficulty: Hard
Correct Answer: 4312*sqrt(6)
Explanation:
Introduction / Context:
This question combines cylinder surface-area formulas with ratio reasoning. The ratio CSA:TSA = 2:5 immediately gives a relationship between height and radius, and then the given TSA lets us compute the exact radius. Finally, volume follows from V = pi*r^2*h. This is a classic multi-step mensuration problem.
Given Data / Assumptions:
Concept / Approach:
Use the ratio to connect CSA and TSA, then derive h in terms of r using TSA/CSA = (h + r)/h. Use CSA to find r, then compute volume.
Step-by-Step Solution:
Verification / Alternative check:
Check TSA using r = 7*sqrt(6) and h = (2/3)r: TSA becomes 3080 cm^2 exactly (with pi = 22/7), confirming consistency.
Why Other Options Are Wrong:
Common Pitfalls:
Mixing CSA with TSA, forgetting the 2*pi*r factor cancels in the ratio, or using (2/5) incorrectly as (5/2).
Final Answer:
4312*sqrt(6)
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