I've done this in a vba macro, but now I have a need to do it in a
cell formula.

In my worksheet, a new row of detail is added daily. In the 'header'
area (rows 1 through 10) I have a cell that needs to make a
calculation based on the value of a cell in the most recently added
(last occupied) detail row. In pseudo code it would be something like
this:

=$B(LastRow) * 23.5

Is there an elegant way to do this?

TIA