Geometry

Question Analysis

The main focus is applying the formula for the area of a ring. We need to find the radii of the outer and inner circles from the given diameter and radius, then calculate the difference between the areas of the outer and inner circles.

 

Key Concept Explanation

The area of a circle is calculated using the formula , where  is the radius. For a ring (annulus), the area  is given by , with  being the radius of the outer circle and  being the radius of the inner circle.

 

Step - by - Step Solution

1. Determine the radii:

The inner radius  cm.

The outer diameter  cm, so the outer radius  cm.

2. Apply the formula for the area of the ring:

Substitute into .

Calculate

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