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 follow these steps:

### Step 1: Write the standard equation of a sphere
The standard equation of a sphere with center \((a, b, c)\) and radius \(k\) is given by:
\[ (x - a)^2 + (y - b)^2 + (z - c)^2 = k^2 \]

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