[rachofsunshine]

The denominator of that fraction is meant to be interpreted as what we would write today as 3.2, not 3x2, and indeed fourth root 100 = about 3.16. The interpunct (the mid-line dot you're interpreting as multiplication) was historically a common way of marking what we now mark with a . character.

[1] https://en.wikipedia.org/wiki/Decimal_separator#English-spea...