# The Golden Ratio The Golden Ratio is the ratio of the sides of a rectangle that can be divided in such a way to form a square and a smaller rectangle that is geometrically similar to the larger one. ![[NGxK6elGBs-587-588-111016.svg.png]] It can be calculated by setting the size of the smaller side to 1: $ \begin{align} \varphi = \frac{c}{1} = \frac{1}{c-1} \\ \varphi = \frac{1}{\varphi-1} \\ \varphi^2 - \varphi - 1 &= 0 \\ \varphi = \frac{1 + \sqrt 5}{2} \end{align} $