Difficulty: Easy
Correct Answer: 7040 sq cm
Explanation:
Introduction / Context:
The curved surface area (CSA) of a cylinder equals the area of a rectangle with height h and width equal to the circumference 2πr. This is a direct substitution exercise once r and h are identified correctly.
Given Data / Assumptions:
Concept / Approach:
Compute 2 * π * 7 * 160 and evaluate numerically, preferably with π = 22/7 to get an exact integer in this setup (common in aptitude problems).
Step-by-Step Solution:
CSA = 2πrh = 2 * π * 7 * 160 = 2240π cm^2With π = 22/7 → CSA = 2240 * (22/7) = 320 * 22 = 7040 cm^2
Verification / Alternative check:
Using π ≈ 3.14 yields 2240 * 3.14 ≈ 7033.6 cm^2, which rounds to 7034–7040; consistent with the exact 22/7 value.
Why Other Options Are Wrong:
6020 and 5052 are too small; 7045 and 7080 overshoot the precise value; 7040 cm^2 matches the exact arithmetic with π = 22/7.
Common Pitfalls:
Using diameter instead of radius; confusing TSA with CSA; arithmetic errors multiplying large factors.
Final Answer:
7040 sq cm
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