The Greek letter φ is pronounced fa √. This letter is a symbol of diameter. For example, to indicate that the diameter of circle A is 20cm, it can be expressed as φ a = 20 cm.

The way to represent the diameter of a circle is: the Greek letter φ (phi, pronounced fa √) plus the letter representing the circle. Such as Φ o, Φ a, followed by connection =, such as Φ a = 30 mm. In drawing and engineering terminology, the diameter can be directly expressed by Φ plus a number, such as Φ 30.

The input method of φ is as follows:

1, hold down the Alt key first, then enter 42677 on the keypad, and then release the ATL key to see the symbol "φ" (press the number 934 in Word and Excel spreadsheets).

2. In Word and Excel, click "Insert-Symbol-Basic Greek" and select the Greek letter PHi (shape φ, pronunciation FAI).

3. Most input methods provide the function of symbol soft keyboard. Open the Greek alphabet soft keyboard and you will find φ.