Calculate the radius of gyration of a circular disc about its diameter.

Explanation

To calculate the radius of gyration of a circular disc about its diameter, we can follow these steps:

### Step 1: Understand the Moment of Inertia
The moment of inertia (I) of a circular disc about its diameter is given by the formula:
\[ I = \frac{1}{4} m r^2 \]
where:
- \( m \) is the mass of the disc,
- \( r \) is the radius of the disc.
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