Answer :

To solve the formula [tex]\( C = \pi d \)[/tex] for [tex]\( d \)[/tex], follow these steps:

1. Begin with the given formula:
[tex]\[ C = \pi d \][/tex]

2. Isolate the variable [tex]\( d \)[/tex]:
To solve for [tex]\( d \)[/tex], we need to isolate it on one side of the equation. We can do this by dividing both sides of the equation by [tex]\( \pi \)[/tex].
[tex]\[ \frac{C}{\pi} = \frac{\pi d}{\pi} \][/tex]

3. Simplify the equation:
The [tex]\( \pi \)[/tex] terms on the right-hand side cancel out.
[tex]\[ \frac{C}{\pi} = d \][/tex]

4. Rewrite the equation:
[tex]\[ d = \frac{C}{\pi} \][/tex]

Thus, the correct solution for [tex]\( d \)[/tex] is:
[tex]\[ d = \frac{C}{\pi} \][/tex]

Therefore, the correct answer is option D: [tex]\( d = \frac{C}{\pi} \)[/tex].