To solve the formula [tex]\( d = r \cdot t \)[/tex] for [tex]\( r \)[/tex], follow these steps:
1. Start with the given formula:
[tex]\[ d = r \cdot t \][/tex]
2. To isolate [tex]\( r \)[/tex], you need to get [tex]\( r \)[/tex] on one side of the equation by itself. To do this, divide both sides of the equation by [tex]\( t \)[/tex]:
[tex]\[ \frac{d}{t} = \frac{r \cdot t}{t} \][/tex]
3. On the right side of the equation, [tex]\( t \)[/tex] divided by [tex]\( t \)[/tex] equals 1, which simplifies the equation to:
[tex]\[ \frac{d}{t} = r \][/tex]
4. Now, the formula solved for [tex]\( r \)[/tex] is:
[tex]\[ r = \frac{d}{t} \][/tex]
Therefore, the correct answer is:
[tex]\[ \boxed{D} \][/tex]
