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    Question

    A right circular cone has a height of 24 cm and a base

    radius of 9 cm. What is the total surface area of the cone, including the base?
    A 594 cm² Correct Answer Incorrect Answer
    B 612 cm² Correct Answer Incorrect Answer
    C 978 cm² Correct Answer Incorrect Answer
    D 625 cm² Correct Answer Incorrect Answer

    Solution

    Slant height (l) of the cone = √(r² + h²) = √(9² + 24²)  = √(81 + 576) = √657 ≈ 25.61 cm. Total surface area = πr(l + r), Total surface area = π × 9 × (25.61 + 9) = π × 9 × 34.61 = 311.49π ≈ 978 cm².

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