使用 TikZ 和 tkz-euclide 绘制莫利三角形的问题

Question

我想说明莫雷定理。所以我编写了以下程序：

\documentclass{article}

\usepackage{tikz}
\usepackage{tkz-euclide}

\begin{document}
\begin{center}
  \begin{tikzpicture}[scale=1.2]
    \tkzInit[ymin=-4.5,ymax=6.5,xmin=-5,xmax=7]
    \tkzClip
    % Triangle vertices
    \tkzDefPoints{-2.5/-2/A,2/4/B,5/-1/C}
    % Angles and trisectors
    % angle A trisectors : (A,TA1) et (A,TA2)
    \tkzFindAngle(C,A,B) \tkzGetAngle{anglea}
    \tkzDefPointBy[rotation=center A angle 1*\anglea/3](C) \tkzGetPoint{TA1}
    \tkzDefPointBy[rotation=center A angle 2*\anglea/3](C) \tkzGetPoint{TA2}
    % angle B trisectors : (B,TB1) et (B,TB2)
    \tkzFindAngle(A,B,C) \tkzGetAngle{angleb}
    \tkzDefPointBy[rotation=center B angle 1*\angleb/3](A) \tkzGetPoint{TB1}
    \tkzDefPointBy[rotation=center B angle 2*\angleb/3](A) \tkzGetPoint{TB2}
    % angle C trisectors : (C,TC1) et (C,TC2)
    \tkzFindAngle(B,C,A) \tkzGetAngle{anglec}
    \tkzDefPointBy[rotation=center C angle 1*\anglec/3](B) \tkzGetPoint{TC1}
    \tkzDefPointBy[rotation=center C angle 2*\anglec/3](B) \tkzGetPoint{TC2}
    % trisectors intersections
    \tkzInterLL(A,TA1)(B,TB2) \tkzGetPoint{U1}
    \tkzInterLL(A,TA2)(B,TB1) \tkzGetPoint{V1}
    \tkzInterLL(B,TB1)(C,TC2) \tkzGetPoint{U2}
    \tkzInterLL(B,TB2)(C,TC1) \tkzGetPoint{V2}
    \tkzInterLL(C,TC1)(A,TA2) \tkzGetPoint{U3}
    \tkzInterLL(C,TC2)(A,TA1) \tkzGetPoint{V3}
    % Draws
    % triangle ABC and points A, B and C
    \tkzSetUpLine[color=black,line width=1pt]
    \tkzDrawPolygon(A,B,C)
    \tkzLabelPoint[black,above left](A){$A$}
    \tkzLabelPoint[black,above right](B){$B$}
    \tkzLabelPoint[black,above right](C){$C$}
    % first trisectors
    \tkzSetUpLine[color=blue!50]
    \tkzDrawLine[add=2 and 2,very thin,dashed](A,TA1)
    \tkzDrawLine[add=2 and 2,very thin,dashed](B,TB1)
    \tkzDrawLine[add=2 and 2,very thin,dashed](C,TC1)
    % second trisectors 2
    \tkzSetUpLine[color=green!50!black]
    \tkzDrawLine[add=2 and 2,very thin,dashed](A,TA2)
    \tkzDrawLine[add=2 and 2,very thin,dashed](B,TB2)
    \tkzDrawLine[add=2 and 2,very thin,dashed](C,TC2)
    % first Morley triangle
    \tkzSetUpLine[color=red]
    \tkzDrawPoints[size=2](U1,U2,U3)
    \tkzDrawPolygon[very thick](U1,U2,U3)
    \tkzLabelPoint[red](U1){$t_a$}
    \tkzLabelPoint[red,below left](U2){$t_b$}
    \tkzLabelPoint[red,above](U3){$t_c$}
    % second Morley triangle
    \tkzSetUpLine[color=orange]
    \tkzDrawPoints[size=2](V1,V2,V3)
    \tkzDrawPolygon[very thick](V1,V2,V3)
    \tkzLabelPoint[orange,left](V1){$s_a$}
    \tkzLabelPoint[orange,right](V2){$s_b$}
    \tkzLabelPoint[orange,below](V3){$s_c$}
  \end{tikzpicture}
\end{center}
\end{document}

代码编译正确，但我对结果有疑问：如果橙色三角形看起来足够等边，那么红色三角形显然不等边。

您能指出我的代码中的错误吗？