How to draw an equilateral triangle with a solid line inside it?

Question

I know how to draw a triangle like so:

\begin{tikzpicture}
%Triangle 2
\node at (2,-1) {triangle 2};
\draw (0,0)--(2,0) node[sloped,pos=0.5]{};
\draw (2,0)--(2,2) node[sloped,pos=0.5]{\arrowR};
\draw (0,0)--(2,2) node[sloped,pos=0.5]{\arrowR};
\end{tikzpicture}

But, here is the figure I wanna draw:

An equilateral triangle with a solid line inside it, could anyone help me in this drawing please?

Answer 1

First nobody can help you since you did not provide how \arrowL and \arrowR are defiend.

I also do not know what you do not understand with the code given here.

You can achieve this triangle by simple extend it by one more line using the corresponding tikz syntax \draw.

EDIT: As mentioned by Rmano this first version is nesting tikz enviroments. So it is better to use the second version with decorations.

\documentclass[border=0.5cm]{standalone}
\usepackage{tikz}

\newcommand{\arrowL}{
    \tikz \draw[latex-] (0,0) -- (0.1,0);
}
\newcommand{\arrowR}{
    \tikz \draw[-latex] (0,0) -- (0.1,0);
}

\begin{document}
    \begin{tikzpicture}
        \draw (0,0)--(8,0) node[sloped,pos=0.5]{\arrowL};
        \draw (4,4)--(8,0) node[sloped,pos=0.5]{\arrowL};
        \draw (0,0)--(4,4) node[sloped,pos=0.5]{\arrowL};
        \draw (4,4)--(4,0) node[sloped,pos=0.5]{};  

    \end{tikzpicture}
\end{document}

...and with labels:

\documentclass[border=0.5cm]{standalone}
\usepackage{tikz}

\newcommand{\arrowL}{
    \tikz \draw[latex-] (0,0) -- (0.1,0);
}
\newcommand{\arrowR}{
    \tikz \draw[-latex] (0,0) -- (0.1,0);
}

\begin{document}
    \begin{tikzpicture}
        \draw (0,0)--(8,0) node[sloped,pos=0.5]{\arrowL};
        \draw (4,4)--(8,0) node[sloped,pos=0.5]{\arrowL};
        \draw (0,0)--(4,4) node[sloped,pos=0.5]{\arrowL};
        \draw (4,4)--(4,0) node[sloped,pos=0.5]{};  

% nodes
 \node[left] at (0,0) {$v$};
 \node[right] at (8,0) {$v$};
 \node[above] at (4,4) {$v$};
 \node[below] at (4,0) {$b$};
 \node[above] at (2,2) {$a$};
 \node[above] at (6,2) {$a$};
    \end{tikzpicture}
\end{document}

a version using decorations:

\documentclass[border=0.5cm]{standalone}
\usepackage{tikz}
\usetikzlibrary{ decorations.markings}

\tikzset{
    arrow/.style={postaction={decorate},
        decoration={markings,mark=at position .5 with {\arrowreversed{latex}}}},
    arrow2/.style={postaction={decorate},
        decoration={markings,mark=at position .5 with {\arrow{latex}}}},
}


\begin{document}
    \begin{tikzpicture}
        ] 
        
        \draw[arrow] (0,0)--(8,0);      
        \draw[arrow] (4,4)--(8,0);
        \draw[arrow] (0,0)--(4,4);
        \draw (4,4)--(4,0);  
    
    % nodes
    \node[left] at (0,0) {$v$};
    \node[right] at (8,0) {$v$};
    \node[above] at (4,4) {$v$};
    \node[below] at (4,0) {$b$};
    \node[above] at (2,2) {$a$};
    \node[above] at (6,2) {$a$};
    \end{tikzpicture}
\end{document}

Answer 2

For an equilateral triangle, with this code:

\documentclass[border=0.5cm]{standalone}

\usepackage{tikz}


\begin{document} 
    \begin{tikzpicture}
        %   Triangle 1
        
        %\draw (0,0)--(2,0)--(60:2)--(0,0)--cycle;
        \draw (2,0)--(0,0) node[midway,below] () {$b$};
        \draw (2,0)--(1,1.732) node[midway,right] () {$a'$};
        \draw (1,1.732)--(0,0) node[midway,left] () {$a'$};
        \draw[-latex] (2,0)--(1,0);
        \draw[-latex] (2,0)--(1.5,0.866);
        \draw[-latex] (1,1.732)--(.5,0.866);
        \draw (1,1.732)--(1,0);
        \node[below] at (0,0) () {$v$};
        \node[below] at (2,0) () {$v$};
        \node[above] at (1,1.732) () {$v$};
    \end{tikzpicture}

\end{document}

you have the output:

If you want only the equilateral triangle, with this code:

\documentclass[border=0.5cm]{standalone}

\usepackage{tikz}


\begin{document} 
    \begin{tikzpicture}
        \draw (0,0)--(2,0)--(60:2)--(0,0)--cycle;
        \draw (1,1.732)--(1,0);
    \end{tikzpicture}
\end{document}

you have this output:

Answer 3

Here a solution with tkz-euclide. You can choose between the following triangles: equilateral half or two one pythagore or pythagoras or egyptian school
golden or sublime euclid or euclide gold cheops two angles isosceles right

\documentclass{standalone}
\usepackage{tkz-euclide}

\tkzSetUpLine[line width=.4pt,color=teal]
\tikzset{arrow/.style={
         decoration={markings,
         mark= at position .5 with {\arrow[scale=2]{>}}}}}  
\begin{document}

\begin{tikzpicture}[scale=1.5,]
\tkzDefPoint(0,0){A}
\tkzDefPoint(4,0){B}
\tkzDefTriangle[equilateral](A,B) \tkzGetPoint{C}
\tkzDefMidPoint(A,B)    \tkzGetPoint{M}
\tkzDrawPolygon(A,B,C)
\tkzDrawSegments[arrow,postaction={decorate}](A,B B,C C,A)
\tkzDrawSegment(C,M)
\tkzLabelPoints(A,B,C)
\end{tikzpicture}

\begin{tikzpicture}[scale=1.5,]
\tkzDefPoint(0,0){A}
\tkzDefPoint(4,0){B}
\tkzDefTriangle[egyptian](A,B) \tkzGetPoint{C}
\tkzDrawPolygon(A,B,C)
\tkzDrawSegments[arrow,postaction={decorate}](A,B B,C C,A)
\end{tikzpicture}    
\end{document}

I take the same code but to inverse the triangle I wrote B,A instead of A,Bidem for the arrow.

\documentclass{standalone}
\usepackage{tkz-euclide}

\tkzSetUpLine[line width=.4pt,color=teal]
\tikzset{arrow/.style={
         decoration={markings,
         mark= at position .5 with {\arrow[scale=2]{>}}}}}  
\begin{document}

\begin{tikzpicture}[scale=1.5,]
\tkzDefPoint(0,0){A}
\tkzDefPoint(4,0){B}
\tkzDefTriangle[equilateral](A,B) \tkzGetPoint{C}
\tkzDefMidPoint(A,B)    \tkzGetPoint{M}
\tkzDrawPolygon(A,B,C)
\tkzDrawSegments[arrow,postaction={decorate}](B,A B,C C,A)
\tkzDrawSegment(C,M)
\tkzLabelPoints(A,B,C)
\end{tikzpicture}

\begin{tikzpicture}[scale=1.5,]
\tkzDefPoint(0,0){A}
\tkzDefPoint(4,0){B}
\tkzDefTriangle[equilateral](B,A) \tkzGetPoint{C}
\tkzDefMidPoint(A,B)    \tkzGetPoint{M}
\tkzDrawPolygon(A,B,C)
\tkzDrawSegments[arrow,postaction={decorate}](A,B B,C C,A)
\tkzDrawSegment(C,M)
\tkzLabelPoints(A,B,C)
\end{tikzpicture}

\end{document}