Geometry

Question Analysis

The main focus is using the area formula for a ring to find the inner radius and then determining the inner diameter.

 

Key Concept Explanation

The area of a ring is calculated by the formula , where  is the area of the ring,  is the outer radius, and  is the inner radius. This formula is based on subtracting the area of the inner circle () from the area of the outer circle ().

 

Step - by - Step Solution

1. Start with the ring - area formula .

Substitute  and  into the formula: .

Divide both sides of the equation by : .

Rearrange the equation to solve for :

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