Question: I am trying to draw something like this in overleaf using Tikzpicture, I need assistance

[![enter image description here](https://i.stack.imgur.com/2lwme.png)](https://i.stack.imgur.com/2lwme.png)

Answer: 
One solution with `tkz-euclide`:

```
\documentclass{article}
\usepackage{tkz-euclide}

\begin{document}
    \begin{figure}
        \centering
        \begin{tikzpicture}[double distance=3pt]
            \clip(-.5,-.5) rectangle (12,5);
            \tkzDefPoints{-5/0/S,0/0/A,3/0/B,1/2/C}
            \tkzDefPointsBy[homothety=center S ratio 2](A,B,C){D,E,F}

            \tkzDrawPolygon(A,B,C)
            \tkzDrawPolygon(D,E,F)
            \tkzLabelPoints[left](A,D)
            \tkzLabelPoints[right](B,E)
            \tkzLabelPoints[above](C,F)
            \tkzMarkAngle[size=5mm,mark=|,arc=l](B,A,C)
            \tkzMarkAngle[size=5mm,mark=none,arc=l](C,B,A)
            \tkzMarkAngle[size=5mm,mark=s,arc=l](A,C,B)
            \tkzMarkAngle[size=10mm,mark=|,arc=l](E,D,F)
            \tkzMarkAngle[size=10mm,mark=none,arc=l](F,E,D)
            \tkzMarkAngle[size=10mm,mark=s,arc=l](D,F,E)
        \end{tikzpicture}
        \caption{Triangles in Tikz}
    \end{figure}
\end{document}

```

[![Similar triangles with tkz-euclide](https://i.stack.imgur.com/ShE4f.jpg)](https://i.stack.imgur.com/ShE4f.jpg)
Here is something to start with.

How to properly make the right angle mark see [here](https://tex.stackexchange.com/a/79999/224762).

```
\documentclass[border=3mm]{article}

\usepackage{tikz}
\usepackage{caption}

\newcommand*{\rechterWinkel}[3]{% #1 = point, #2 = start angle, #3 = radius
    \draw[shift={(#2:#3)}] (#1) arc[start angle=#2, delta angle=90, radius = #3];

}

\begin{document}

    \begin{figure}
        \centering

    \begin{tikzpicture}     

        \draw (0,0) -- (1,1) -- (3,0) -- cycle;
    \node[xshift=-2mm](A) at (0,0) {A};
    \node[yshift=2mm](C) at (1,1) {C};
    \node[xshift=2mm](B) at (3,0) {B};
    \rechterWinkel{0.2,0}{1}{.2} %A

    \rechterWinkel{1,1.05}{-127}{.2} %B
    \rechterWinkel{1,1.04}{-127}{.25} %B

    \rechterWinkel{2.8,0}{90}{.1} %C   
    \rechterWinkel{2.75,0}{90}{.128} %C
    \rechterWinkel{2.7,0}{90}{.155} %C

        \end{tikzpicture}

    \begin{tikzpicture}     

    \draw (0,0) -- (2,2) -- (5,0) -- cycle;
    \node[xshift=-2mm](D) at (0,0) {D};
    \node[yshift=2mm](F) at (2,2) {F};
    \node[xshift=2mm](E) at (5,0) {E};

    \end{tikzpicture}

    \caption{Triangle in Tikz}
    \end{figure}

\end{document}

```

[![enter image description here](https://i.stack.imgur.com/mVUXC.png)](https://i.stack.imgur.com/mVUXC.png)