This is not a question involving numbers and stuff, but suddenly had this basic question in mind: What are the different symbols that different people use for denoting an angle? (I mean, we usually use this $\angle$ symbol for denoting an angle; some people use the one with a c-curve, something like that).
I suddenly had this question as I was going through bunch of question papers of different MO’s in different countries, and just realised that they use different symbols to denote an angle. This may seem to be a very simple and basic question, but I need it because I just know a bunch of symbols in math and knowing more symbols helps me in exams. Thanks in advance.
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$\begingroup$$\angle$ is usually used to denote a standard angle, whereas $\measuredangle$ is used to denote a directed angle.
That is, given two non-parallel lines $\ell$ and $m$, the directed angle $\measuredangle(\ell, m)$ denotes the measure of the angle starting from $\ell$ and ending at $m$, measured counterclockwise.
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