TikZ作品集「一般角の動径」

210°

\documentclass[dvipdfmx]{jsarticle}
\usepackage{tikz}

\usetikzlibrary{angles}  %pic angle を使うため
\usetikzlibrary{quotes}  %角度記号に"角度"を入れるため

\begin{document}
\begin{tikzpicture}[scale=0.6]
% 
% 点の定義
\coordinate (O) at (  0:0);%原点O
\coordinate (X) at (  0:6);%始線X
\coordinate (P) at (210:6);%動径P
\coordinate (W) at (180:6);%西

\draw (O) node [below] {O};

% 180°分
\pic [->,>=stealth,fill=orange!5!white,draw=orange,very thick,"$180^{\circ}$",angle radius=1cm,angle eccentricity=1.3] {angle=X--O--W};
% 30°分
\pic [->,>=stealth,fill=green!5!white,draw=green!60!black,very thick,"$30^{\circ}$",angle radius=1cm,angle eccentricity=1.3] {angle=W--O--P};

% 210°分
\pic [->,>=stealth,draw=red,very thick,"$210^{\circ}$",angle radius=2cm,angle eccentricity=1.2] {angle=X--O--P};

%始線・動径・補助線
\draw[thick] (P)--(O)--(X);
\draw[dashed] (O)--(W);

\draw[fill=black] (O) circle [radius=2pt];

%説明
\draw (340:6) node [left] {$\colorbox{orange!30!white}{$180^{\circ}$}+\colorbox{green!30!white}{$30^{\circ}$}=\colorbox{red!20!white}{$210^{\circ}$}$};
\end{tikzpicture}
\end{document}