Geometry

Question Analysis

The main focus is applying the formula for the area of a ring. We need to first find the outer and inner radii from the given diameters and 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 , 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 outer diameter  mm, so the outer radius  mm.

The inner diameter  mm, so the inner radius  mm.

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

Substitute into