Why 圓周率p 是以一個希臘文字命名?

好多數學，物理等專有名詞，都係用希臘字母黎做代號，用pi嘅原因如下：

The letter π

圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/2/2e/Pi-symbol.svg/80px-Pi-symbol.svg.png



Main article: pi (letter)
The name of the Greek letter π is pi, and this spelling is used in typographical contexts where the Greek letter is not available or where its usage could be problematic. When referring to this constant, the symbol π is always pronounced like "pie" in English, the conventional English pronunciation of the letter.
The constant is named "π" because it is the first letter of the Greek words περιφέρεια 'periphery' and περίμετρος 'perimeter', i.e. 'circumference'.
π is Unicode character U+03C0 ("Greek small letter pi").

Pi (uppercase Π, lower case π or ϖ) is the sixteenth letter of the Greek alphabet. In the system of Greek numerals it has a value of 80.
In Greek, the letter is pronounced /piː/ (as in pea); in modern English, it is pronounced /paɪː/ (as the word pie), in particular when referring to the mathematical constant (see below). In words, it is pronounced /p/. In Modern Greek, the sequence of letters μπ represents the /b/ sound, as in boy (the second letter of the Greek alphabet is now pronounced /v/ as in very).

其實許多數學的簡稱都是以希臘文字命名的，例如θ、ε，這是一個傳統
而且希臘文字比中文易寫，寫一個π當然此寫「圓周率」三個字容易