TikZ Angle Label - Help it "fit" better?

Question

I have the following drawn with TikZ

using the code

\documentclass{article}
\usepackage{tikz}
\usepackage{tkz-euclide}
\usetkzobj{all}
\begin{document}
\begin{tikzpicture}
\coordinate (O) at (0,0);
\draw (O) circle (3);
\coordinate[label = above left:$M$] (M) at (130:3);
\coordinate[label = above:$N$] (N) at (80:3);
\coordinate[label = below:$A$] (A) at (240:3);
\coordinate[label =below right:$B$] (B) at (300:3);
\draw (A) -- (M) -- (B);
\draw (A) -- (N) -- (B);
\tkzMarkAngle[draw = black, fill = white, opacity=1](A,M,B)
\tkzLabelAngle[pos = 0.8](A,M,B){$x$}
\tkzMarkAngle[pos = 0.2,draw = black, fill = white, opacity=1](A,N,B)
\tkzLabelAngle [pos=0.8](A,N,B){$27 ^{\circ}$}
\end{tikzpicture}
\end{document}

Notice however, tht the 27 degrees does not fit in very nicely. How can I adapt the code to try and move the 27 a bit "lower" so that it fits in better, as well as the angle mark?

Also, how can I get two "double arrows" in the middle of lines AM and BN, to indicate that they are 'parallel'?

Answer 1

1. Use size=<length> for \tkzMarkAngle to control the radius for the arc used for the mark.

2. Use the pos key in \tkzLabelAngle to move the label away (or closer) to the vertex of the angle.

   • You could also try reducing a little the font size:

     \tkzMarkAngle[size=1.3,draw = black, fill = white, opacity=1](A,N,B)
     \tkzLabelAngle[pos=1.1,font=\scriptsize](A,N,B){$27 ^{\circ}$}
     

3. Although tkz-euclide provides \tkzMarkSegments to place marks on segments, I opted below for a decoration using arrows, to draw the two sets of arrows to represent parallelism.

4. Your lines AM and BN are not parallels. I provided some code below to get real parallel lines (in the edit history of this answer there's a version with the original non-parallel lines).

The code:

\documentclass{article}
\usepackage{tkz-euclide}
\usetkzobj{all}

\tikzset{
  middlearrows/.style={
    decoration={             
      markings, 
      mark=at position 0.48 with {\arrow{triangle 45};},
      mark=at position 0.52 with {\arrow{triangle 45};}
      },
  postaction={decorate}
  }
}

\begin{document}

\begin{tikzpicture}[line join=round]
\coordinate (O) at (0,0);
\coordinate[label = above left:$M$] (M) at (130:3);
\coordinate[label = above:$N$] (N) at (80:3);
\coordinate[label = below:$A$] (A) at (240:3);

% parallel to MA passing through N
\tkzDefLine[parallel=through N](M,A)
\tkzGetPoint{Aux}
% Intersections between the parallel and the circle
\tkzInterLC(N,Aux)(O,M)
\tkzGetPoints{N}{B}
\tkzLabelPoints(B)

\tkzDrawSegments(M,B N,A)

\tkzMarkAngle[draw = black, fill = white, opacity=1](A,M,B)
\tkzLabelAngle[pos = 0.8](A,M,B){$x$}

\tkzMarkAngle[size=1.4,draw = black, fill = white, opacity=1](A,N,B)
\tkzLabelAngle[pos=1.15,font=\scriptsize](A,N,B){$27 ^{\circ}$}

\draw[middlearrows] (A) -- (M); 
\draw[middlearrows] (B) -- (N); 

\tkzDrawCircle[R](O,3cm)
\end{tikzpicture}

\end{document}

The result: