\documentclass{standalone}

\usepackage{tikz}

\usetikzlibrary
{
   calc,math
}

\usepackage{tkz-euclide}
%%!
%%! For older versions of package tkz-euclide
%%! you may need uncomment the following line:
%   \usetkzobj{all}
%%!



\begin{document}
   \begin{tikzpicture}      
       \tikzmath{\N=5;}
       \tikzmath{\dN=1/\N;}
       
       \coordinate (A) at (1,2);
       \coordinate (B) at (-3,1);
       \coordinate (C) at (2,-3);
       
       %Draw nodes with titles
       \foreach \P/\anchor in {A/west,B/east,C/north west}
       {
          \filldraw (\P) circle(1pt) node[anchor=\anchor] {$\P$};
       }
       
       \draw (A) -- (B) -- (C) -- cycle;
       
       \foreach \n in {1,2,...,\N}
       {
          \tikzmath{\t=\n*\dN;}
          
          \coordinate (P) at ($(A)!\t!(B)$);
          \coordinate (Q) at ($(A)!\t!(C)$);
          \tikzmath{\s=-0.25;}
          \draw[dotted]
             ($(P)!\s!(Q)$) -- ($(Q)!\s!(P)$)
             node[right] {$t=\t$};
       }
       
       \foreach \n in {1,2,...,\N}
       {
          \tikzmath{\s=\n*\dN;}
          
          \coordinate (P) at ($(B)!\s!(A)$);
          \coordinate (Q) at ($(B)!\s!(C)$);
          \tikzmath{\t=-0.25;}
          \draw[dotted]
             ($(P)!\t!(Q)$) -- ($(Q)!\t!(P)$)
             node[anchor=north east] {$s=\s$};
       }
       
    \end{tikzpicture}
\end{document}