Geometry

Question Analysis  

The main focus is using the formula for the area of a ring. Given the radii of the outer and inner circles (the large disc and the cut - out smaller disc), we need to calculate the difference between their areas.

Key Concept Explanation  

The area of a circle is , where  is the radius. For a ring, the area , with  as the outer radius and  as the inner radius. This formula subtracts the area of the inner circle from the area of the outer circle.

Step - by - Step Solution  

1. Identify the outer and inner radii:

The outer radius  cm (radius of the large disc).

The inner radius  cm (radius of the small disc that is cut out).

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

Substitute into .

Calculate  and .

Then