# Circle with labelled rotated radians

I'm wondering how I can reproduce the following diagrams using TeX:

I realize this question is similar to this other question, however I'm not nearly experienced enough to be able to translate from the answer to that question to the above diagram. (Label rotation, explicit set of rotations, nested circles with partial radians, etc.)

Thank you for any assistance you can offer.

• E.g. in TikZ you can use polar coordinates, like \node at (30:1) {$\frac{1}{12}$}. – Tom Bombadil Jun 3 '13 at 18:38

One possibility using polar coordinates:

\documentclass{article}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{arrows}

\begin{document}

\begin{tikzpicture}
\draw (0,0) circle (3cm);
\foreach \mangle/\value in {0/{$0,1$},30/$\dfrac{1}{12}$,45/$\dfrac{1}{8}$,60/$\dfrac{1}{6}$,90/$\dfrac{1}{4}$,120/$\dfrac{1}{3}$,180/$\dfrac{1}{2}$,270/$\dfrac{3}{4}$}
{
\draw (0,0) -- (\mangle:3.5cm);
\node at (\mangle:4) {\value};
}
\begin{scope}[yshift=8cm,>=latex]
\draw (0,0) circle (3cm);
\draw (0,0) circle (1.7cm);
\draw[-] (0,0) -- +(60:3.5cm) ;
\draw[-] (0,0) -- +(30:3.5cm) ;
\draw[->] (0,0) -- node[pos=0.95,left=3pt ] {$r_2$} +(60:3cm) ;
\draw[->] (0,0) -- node[pos=0.6,right=6pt] {$r_1$} +(30:1.7cm) ;
\node at (45:3.3) {$s_2$};
\node at (45:2) {$s_1$};
\node at (45:1) {$\theta$};
\end{scope}
\end{tikzpicture}

\end{document}


• Perfect! Now I'll dig through whatever documentation I can find to try to understand all of that. ^_^ – GothAlice Jun 3 '13 at 19:05
• @GothAlice there's the pgfmanual; the minimal introduction to TikZ. Search for key terms: polar coordinates, \foreach. – Gonzalo Medina Jun 3 '13 at 20:53