The diagonal (approximate, to four decimal places) of a 1 x 1 square, also known as Pythagoras's Constant, and therefore also the ratio (1:1.4142) for calculating the diagonal side [..]

The Golden Number (to four decimal places). Also known as the Golden Section, Divine Proportion, and phi (pronounced 'fy' as in the word 'fly') the twenty-first lette [..]

Pi, normally represented by the Greek letter pi (P) symbol π. Pi is typically used for calculating the area (π x radius squared) or circumference (π x diameter) of a circle. Pi has an in [..]

Four beats to the bar, the most common rhythm in music.

The most superstitious number, 13 affects business in surprising ways through absenteeism, cancellations, and design. Western airlines, for example, tend not to have seats and rows numbe [..]

Gun Salute - Traditional honour given to royalty and heads of state, derived from the old signal of peaceful intent, when multiple firing practically removed capability for immediate thr [..]

Carat/Karat - The purest form of gold (karat is US-English spelling, too soft for jewellery, hence gold jewellery is made of 22-carat, 18-carat, or 9-carat gold, etc., in which other met [..]

Twenty four hours a day, seven days a week.

The key or crucial question in a particular issue, deriving from an old US radio quiz game show called Take It Or Leave It, in which $64 was the top prize (it was an old show..). The sho [..]

The theory that 20% of effort produces 80% of results, and very many similar effects; also known as Pareto Rule or Pareto Principle, after its originator.