Aspect Ratios - more proper to use a : or an X?

[JaredSMark]

I've always wondered... we have a colon, an X, and the decimals when talking about aspect ratios. 4X3, 4:3 and a 1.33 (or 1.33:1) all seem like the same thing. The colon is for division, so does that mean the X is for multiplication? It seems that way when talking about a resolution but I'm not sure about aspect ratios.

Is there a proper time to use each one of these and can someone give me the lowdown on it?

 

[David Jimerson]

The colon denotes a ratio; the X denotes dimensions. Colon = "to"; X = "by." Thus, 4x3 and 16x9 are more proper than 4:3 and 16:9, as the colon should really be followed by a 1.