A right circular cone has slant height 10 m and vertical height 8 m. What is the area of its curved (lateral) surface?
Aptitude
Volume and Surface Area
Difficulty: Easy
Choose an option
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A56π m^2
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B60π m^2
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C64π m^2
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D188.5 m^2 (approx.)
Answer
Correct Answer: 60π m^2
Explanation
Problem Restatement
Compute the lateral surface area (CSA) of a cone given its slant height and vertical height.
Given data
- Slant height, l = 10 m
- Vertical height, h = 8 m
Concept / Formulae
- Radius from Pythagoras: r = √(l^2 − h^2)
- Curved surface area: CSA = πr l
Step-by-step calculation
r = √(10^2 − 8^2) = √(100 − 64) = √36 = 6 mCSA = π × 6 × 10 = 60π m^2 ≈ 188.50 m^2
Final Answer
Curved surface area = 60π m^2 (≈ 188.5 m^2).