Difficulty: Medium
Correct Answer: 154√5 cm2
Explanation:
Introduction / Context:
We are given base area and height. From base area A_b = πr^2, find r, then slant height l = √(r^2 + h^2), and finally CSA = π r l.
Given Data / Assumptions:
Concept / Approach:
Compute r from r^2 = 154 / π, then l, then CSA symbolically for an exact surd answer.
Step-by-Step Solution:
r^2 = 154 / (22/7) = 49 ⇒ r = 7 cml = √(r^2 + h^2) = √(49 + 196) = √245 = 7√5CSA = π r l = (22/7) * 7 * 7√5 = 154√5 cm2
Verification / Alternative check:
Dimensional check: area units cm2.
Why Other Options Are Wrong:
154√2 cm2 uses wrong sum under root; 11 and 5324 cm2 are invalid magnitudes; 308 cm2 would be π r h or misapplied formula.
Common Pitfalls:
Using height in place of slant height in CSA; not extracting r correctly from base area.
Final Answer:
154√5 cm2
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