Geometry question, octagon measurements

[JSnover]

I've seen all the formulas for regular octagons but why have I not seen a simple, quick and dirty ID/OD form? In other words, if all sides and angles are equal, wouldn't there be a predictable relationship between the incircle and the circumcircle (the distance across the flats vs the distance across the corners)?
I played with some numbers today with a 1" radius of the incircle and it looks like the circumcircle = the incircle(1.082)
So At 2" across the flats, it should measure 2.164 across the corners.
Does that make sense?
Could I use 1.082 as a constant for octagonal work?

[theperfessor]

Sure can, it's 1.0824:1 corner to flat ratio.

[JSnover]

Thanks! I was pretty sure, just didn't look in the right places.