\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc}

\newlength\zjw%直角标记宽度
\zjw=7pt
\newcommand\zjbj[4][]{%
\draw[#1] let \p1=(#2),\p2=(#4),\p0=(#3),
\n1={atan2(\y1-\y0,\x1-\x0)},
\n2={atan2(\y2-\y0,\x2-\x0)} in
(#3)++(\n1:\zjw)--++(\n2:\zjw)--++(\n1:-\zjw);
}

\newlength\hur%弧半径
\newlength\huj%字母与弧的间距
\hur=7pt
\huj=5pt
\newcommand\hubj[5][]{%
\draw[#1] let \p1=(#2),\p2=(#4),\p0=(#3),
\n1={atan2(\y1-\y0,\x1-\x0)},
\n2={atan2(\y2-\y0,\x2-\x0)},
\n3={Mod(\n2-\n1,360)} in
(#3)++(\n1:\hur)arc[start angle=\n1,delta angle=\n3,radius=\hur]
(#3)+(\n1+0.5*\n3:\hur+\huj) node {$#5$};
}

\begin{document}

\tikz{
\coordinate[label=right:$A$] (A) at (2,0);
\coordinate[label=above:$B$] (B) at (1.75,1.75);
\coordinate[label=left:$C$] (C) at (0,1.5);
\draw (A)--(B)--(C)--cycle;
\zjbj ABC
\hubj ACBx
\hubj BACy
}
\tikz{
\coordinate[label=right:$A$] (A) at (2,0);
\coordinate[label=below left:$B$] (B) at (1.75,1.75);
\coordinate[label=below:$C$] (C) at (0,1.5);
\draw (A)--(B)--(C)--cycle;
\hubj BCAx
\hubj CABy
\hubj ABCz
}
\tikz{
\draw (0,0.5)--(0,0)--(0.5,0)(0,0)--(0,0,0.7);
\zjw=4pt
\zjbj{0,0.5}{0,0}{0.5,0}
\zjbj{0,0,0.7}{0,0}{0.5,0}
\hur=4pt
\hubj{0,0.5}{0,0}{0,0,0.7}{}
}
\tikz{
\coordinate[label=right:$A$] (A) at (2,0);
\coordinate[label=right:$B$] (B) at (1.75,1.75);
\coordinate[label=left:$C$] (C) at (0,1.5);
\draw (A)--(B)--(C)--cycle;
\zjbj[red,thick]ABC
\hubj[red,thick]ABCz
}

random test:

\foreach \i in {1,...,11} {
\tikz{
\coordinate (A) at (rand,rand);
\coordinate (B) at (rand,rand);
\coordinate (C) at (rand,rand);
\draw (A)node{A}--(B)node{B}--(C)node{C};
\zjbj[red,thick]ABC
\hubj[blue,thick]ABC\beta
}}

\end{document}