97.645.
The tenth digit is 6. The digit after that is 4, and it is not up to 5, so we round it down. If it was up to 5 or more we would have added 1 more to the 6 to become 7, but since it is not up to we leave the 6 that way.
97.645 ≈ 97.6 rounded to the nearest tenth.