# What does the colon in Tikz coordinates mean?

``````\draw (0,0) -- (60:.75cm) arc (60:180:.75cm);
``````

What does the colon in `(60:.75cm)` mean? Normally, I'd define a normal point there.

• Figured it out and wrote a neat answer, but apparently I can't post it within 8 h of asking, it told me AFTER letting me write the answer!! (this is a bug report) – Nazia Mar 7 '12 at 20:32
• That's hilarious, the same second! – Werner Mar 7 '12 at 20:37
• @Werner Well, that's a first. – Torbjørn T. Mar 7 '12 at 20:38

The colon signifies that polar coordinates are being used. `(60:.75cm)` means the point that is at an angle of 60° and a distance of 0.75cm from the origin.
The implicit form for `canvas polar` coordinates is the following: you specify the angle and the distance, separated by a colon as in `(30:1cm)`.
This also holds for other coordinate systems like `xyz polar`. Alternatively, if you're not interested in this shorthand notation, TikZ also provides
``````\pgfpointpolar{<degree>}{<x-radius>/<y-radius>}
where `<y-radius>` is optional. See section 70 Specifying Coordinates (p 571) of the documentation.