As you may know, the 8 would be located in the hundreaths place.
2.3892
If the number right of 8 is five for less, it says the same. If it's 5 or more, then 8 would change. In this case, 9 is more than 5 meaning that 8 becomes 9. However, we aren't quite finished yet. 9 and everything left of that number must become 0.
Your answer would be 2.39.