|≈||approximately equal to|
|digits||indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …)|
1/4 circle or quarter circle is equal to 360°/4 = 90°. Plural name is quarter circles.
A revolution is a unit of angle equal to 360°, defined as a complete turn around a circle. Plural name is revolutions.
You can find the conversion in other languages in the following: