# Draw a triangle that encloses points

Consider the following TikZ code.

\begin{tikzpicture}
\node[circle,fill=red] (1) at (4,7.5)  {};
\node[circle,fill=green ] (2) at (8,8)  {};
\node[circle,fill=blue] (4) at (5,7)  {};
\node[circle,fill=violet] (3) at (8,5)  {};
\node[circle,fill=orange] (5) at (9,4.5)  {};

\node[circle,fill=red] (11) at (2,4)  {};
\node[circle,fill=green ] (22) at (4,5)  {};
\node[circle,fill=blue] (44) at (5,4)  {};
\node[circle,fill=violet] (33) at (1,8)  {};
\node[circle,fill=orange] (55) at (3,6.5)  {};
\end{tikzpicture}


That produce the following

I want to draw two triangles as follows

How we can draw those?

• Do you want those triangles to be automatically computed even if you modifiy the position of your initial points or do you want to add those triangles to this specific drawing? Commented Feb 5, 2022 at 22:30
• I want add those triangles to this specific drawing.
– tstt
Commented Feb 5, 2022 at 22:32

If I compile this:

\documentclass[12pt]{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\node[circle,fill=red] (1) at (4,7.5)  {};
\node[circle,fill=green ] (2) at (8,8)  {};
\node[circle,fill=blue] (4) at (5,7)  {};
\node[circle,fill=violet] (3) at (8,5)  {};
\node[circle,fill=orange] (5) at (9,4.5)  {};
\draw[thick,color=red] (10,3)--(8,9)--(2.5,8)--(10,3);

\node[circle,fill=red] (11) at (2,4)  {};
\node[circle,fill=green ] (22) at (4,5)  {};
\node[circle,fill=blue] (44) at (5,4)  {};
\node[circle,fill=violet] (33) at (1,8)  {};
\node[circle,fill=orange] (55) at (3,6.5)  {};
\draw[thick,color=red] (-1,10)--(9.5,3)--(2,3)--(-1,10);
\end{tikzpicture}
\end{document}


what I get is this:

• Very very good. +1. Commented Feb 6, 2022 at 12:48