its a 79.54
Depends on the teacher and/or school policy. You would need to ask them.
As skieurope said, it varies from place to place.
In my state’s high schools, grades are rounded to the nearest whole numbers, so your 79.54 would be considered an 80 (B).
At the CC I’m dual enrolled at, there is no rounding at all. So, a 89.9999 would be considered a B, a 79.999 a C, and so on.