In mathematics, 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, which is about 1.6180. We use the Greek letter ϕ to represent it. The golden ratio is also the solution of the quadratic equation x ^2 − x − 1 = 0. We see the golden ratio everywhere in nature because it appears in some patterns, including the spiral arrangement of leaves and other plant parts.

## Boltzmann’s Constant

The fundamental constant of physics, the Boltzmann constant, is one of the seven "defining constants" that have been given exact definitions.