Geometry

Question Analysis

The main focus is using the ratio of radii of two concentric circles and the area of the ring to find the outer radius. We'll apply the ring - area formula, represent the radii based on the ratio, and solve for the unknown variable to determine the outer radius.

Key Concept Explanation

The area of a ring is calculated by , where  is the outer radius and  is the inner radius. When the radii are in a given ratio, we can express them as multiples of a common variable to simplify the equation - solving process.

Step - by - Step Solution

1. Let the outer radius  and the inner radius  (x > 0).

2. Substitute into the ring - area formula: .

3. Since