A sizes (1:√2 ratio) are related to the 'silver ratio' (not gold) which is "1:1+√2". Regardless of names of precious metals, its a ratio using simpler numbers

A sizes (1:√2 ratio) are related to the 'silver ratio' (not gold) which is "1:1+√2". Regardless of names of precious metals, its a ratio using simpler numbers than "letter" format, which generally means it's more aesthetically pleasing [Edit] it should be noted that (arguably) many Gothic cathedrals are based on a √2 ratio