In England, ratios are often also denoted using ':' ... But these are all whole number ratios. You would never see 1 : 3.141592653.

A bit OT, but further to the point, implicit to most of these discussions, that if it can be done some way, someone does it that way...
At least in the States, film review magazines commonly refer to screen ratios as '1.33:1' (i.e., 4:3 television or pre-Academy-standard film), '1.37:1' (standard 'Academy' ratio), '1.85:1' (standard (?) theatrical ratio), '2.35:1' (theatrical wide-screen), '1.66:1', '1.78:1', etc., etc.