Geometry

Question Analysis
This question applies the surface area formula in a real-world context (an ice cream cone).
The main focus is on recognizing that the base is excluded, so only the lateral area is needed.

Key Concept Explanation
Total surface area of a cone = πr² (base) + πrl (lateral).
But if the base is open, only the lateral surface is considered:
Lateral surface area = πrl

Step-by-Step Solution
Given: r = 4 cm, l = 9 cm
Lateral area = π × 4 × 9 = 36π cm²

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