The symbol used by mathematicians to represent the ratio of a circle's circumference to its diameter is the lowercase Greek letter π, sometimes spelled out as pi.[1]

The Greek small letter π (pi) is used in trigonometry as a constant to represent a half-rotation around a circle in radians. The value of π is approximately 3.14159 and appears in many math …

Oct 21, 2025 · pi, in mathematics, the ratio of the circumference of a circle to its diameter. The symbol π was devised by British mathematician William Jones in 1706 to represent the ratio …

Draw a circle with a diameter (all the way across the circle) of 1. Then the circumference (all the way around the circle) is 3.14159265... a number known as Pi. Pi (pronounced like "pie") is …

The pi symbol (π) is a Greek letter used to represent the ratio of a circle’s circumference to its diameter. It’s been used in this way for over 250 years.

It is defined as the ratio of a circle's circumference to its diameter, and it also has various equivalent definitions. It appears in many formulas in all areas of mathematics and physics. It …

The value of pi is the ratio of the circumference of a circle to its diameter. The pi symbol is denoted as π. It is also called Archimedes' constant which was named after the Greek …

Learn about the Greek letter Pi (π), its pronunciation, usage examples, and common applications in mathematics, science, and engineering.

The pi symbol (Π π) is the 16th letter of the Greek alphabet. Learn its meaning, see uppercase 'Π' and lowercase 'π' forms, and easily copy and paste the symbol for your use.

Pi is an irrational number. An irrational number does not have a repeating pattern and does not end, so it can only be approximated. Calculated to one hundred places after the decimal: π ≈ …