Geometry

Question Analysis

The main focus is applying the formula for the area of a ring, which requires determining the radii of the outer and inner circles and then calculating the difference in their areas.

 

Key Concept Explanation

The area of a circle is given by , where  is the radius. For a ring, the area  is calculated as , with  being the outer radius and  the inner radius.

 

Step - by - Step Solution

1. Determine the radii: The inner radius  cm. The outer radius  cm.

2. Use the ring - area formula:

Substitute into .

Calculate

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