Question

What is a golden ratio?

Answer 1

The ratio for length to width of rectangles of $1.61803398874989484820$ has been considered the most pleasing to the eye. This ratio was named the golden ratio by the Greeks.

Two quantities are in the golden ratio if their ratio is the same as the ratio of their sum to the larger of the two quantities. Expressed algebraically, for quantities $a$ and $b$ with $a>b>0,$

$\frac{a+b}{a}=\frac{a}{b}=:\phi$