Answer:
The distance from the Sun to Neptune is 29,41 AU.
Step-by-step explanation:
We know, from the sentence, that the orbit of Neptune has an average diameter around 8.80*10⁹km.
Now, we can calculate the radius of this orbit, which is equivalent to the distance from thsi planet to the Sun. Let's recall tha the radius is the half of the diameter.

Ok, we know that 1.496*10¹¹m is an AU, therefore we have:

Finally, the distance R is 29,41 AU.
I hope it helps you! :)