Geometry

Question Analysis

This question focuses on calculating the area of a circle given its diameter. The key is to use the relationship between the diameter and radius and then apply the formula for the area of a circle.

Key Concept Explanation

The formula for the area of a circle is , where is the area and is the radius. The radius is half of the diameter , i.e., .

Step - by - Step Solution

1. First, find the radius. Given that the diameter , then the radius .

2. Then, substitute the radius into the area formula:

.

Replace with 9:

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