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A hollow (open) right circular cone has base radius R and vertical height H. What is its curved (lateral) surface area?
- pi*R*sqrt(R² + H²)
- pi*R²*sqrt(R² + H²)
- 2*pi*R*sqrt(R² + H²)
- pi*R*(R + H)
Correct answer: pi*R*sqrt(R² + H²)
Solution
The slant height is l = sqrt(R² + H²), and the curved surface area of a cone is pi*R*l, giving pi*R*sqrt(R² + H²).
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