Re: Concise Circular No 28
Bjørn Kisbye Engsig
We shouldn't forget that some of these integer ratios are indeed exact, while others aren't. 127/5 is exactly 25.4 (in to mm) but 32/35 is not exactly 0.9144 (yard to m). This is of course the beauty of (in particular circular) slide rules where integers may be easier to remember. I do also recall that 355/113 is a much closer approximation than 22/7 to pi, but neither are exact. I own another circular slide rule with ratios mentioned, namely those used by the graphics and printing industry. /Bjørn _______ Sent from my Sinclair ZX81

