It does help though knowing which type of curve it is, thank you. I worked it backwards, using a couple different parabola calculators. But the result was, I had to junk my findings because I worked it as a parabola and OPs spreadsheet - which I've already found incredibly useful - is for cat curves.

When you're dealing with seam allowances and fixed lengths, it pays to be exact. But I try to be a friendly pedantic.