### Golden ratio

Two quantities are in the golden ratio if that is the same as the quotient of their sum and the larger of the two quantities

where *a* > *b* > 0.

##### Explanation

You can calculate the golden ratio as

With the quadratic formula you get

with as positive solution

and as negative solution

As the numbers *a* and *b* are both positive, the negative solution is not valid.

##### Additional information

The letter *φ* (phi) is from the old Greek sculpter Phidias, who wrote a book about the golden ratio.