# What is a common symbol for angles and what are semantic differences?

I've just seen that LaTeX offers at least three symbols for denoting angles:

$\text{\sphericalangle}:\sphericalangle ABC \\\text{\measuredangle}:\measuredangle ABC\\\text{\angle}: \angle ABC$

I think I've understood that a spherical angle is something different than an angle in euclidean geometry.

So I have some questions to the notation of angles:

• What is the semantic difference of $\angle ABC$ and $\measuredangle ABC$?
• Which symbol is commonly used in literature? Please note:
• The symbol might be not in the list from above
• I know this is a loose quesiton. Please give at least one book that makes use of the notation you think is most common. (e.g. these German lecture notes make use of $\angle$ and $\sphericalangle$. The difference seems to be that $\measuredangle$ is the size of the angle whereas $\angle$ denotes the angle itself. So when I understand it correctly, in a rectangle ABCD you could say: $\sphericalangle ABC = \sphericalangle BCD$ and $\angle ABC \neq \angle BCD$)
• If there is a "mathematical style guide" that makes notes which notation to use for angles it would be an answer I'd appreciate very much!
• Are there differences in German mathematics / English mathematics? E.g. just like I think Americans write $1/4$ rather than $\frac{1}{4}$ in contrast to Germans.

(I would also like to know what you think which symbol I should use for angles in euclidean geometry. How well known is the difference of these notations? So, do you think the choice of symbol matters?)

In Italy, for instance, the widespread notation for angle $$ABC$$ is $$A\hat{B}C$$.
Marvin Jay Greenberg in his "Euclidean and non-Euclidean geometries" (1974) uses instead $$\sphericalangle ABC$$.