diff --git a/documents/GeoTopo/figures/triangle-2.tex b/documents/GeoTopo/figures/triangle-2.tex
index e5cb0cf..9d1cdbc 100644
--- a/documents/GeoTopo/figures/triangle-2.tex
+++ b/documents/GeoTopo/figures/triangle-2.tex
@@ -12,8 +12,8 @@
     \tkzMarkAngle[arc=l,size=0.7cm,color=red,fill=red!20](Phelper2,C,PaboveRight)
     \tkzLabelAngle[pos=0.4](Phelper2,C,PaboveRight){$\alpha$}
     \tkzLabelAngle[pos=-0.4](Phelper,C,A){$\alpha''$}
-    \tkzLabelAngle[pos=0.4](B,A,C){$\alpha$}
-    \tkzLabelAngle[pos=0.4](C,B,A){$\beta$}
+    \tkzLabelAngle[pos=0.4](B,A,C){$\alpha'$}
+    \tkzLabelAngle[pos=0.4](C,B,A){$\beta'$}
     \tkzLabelAngle[pos=0.4](PaboveLeft,C,Phelper){$\beta$}
     \tkzLabelAngle[pos=0.4](A,C,B){$\gamma$}
     \tkzDrawLine(A,B)