Find the equation of a sphere whose centre is `(3,1,2)` radius is `5.`

Explanation

To find the equation of a sphere with a given center and radius, we can use the standard formula for the equation of a sphere in three-dimensional space. The standard equation of a sphere with center \((h, k, l)\) and radius \(r\) is given by:

\[ (x - h)^2 + (y - k)^2 + (z - l)^2 = r^2 \]

**Step 1: Identify the center and radius.**
- The center of the sphere is given as \((3, 1, 2)\).
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