diff --git a/Snap_rounding_2/doc_tex/Snap_rounding_2_ref/intro.tex b/Snap_rounding_2/doc_tex/Snap_rounding_2_ref/intro.tex
index 9afe7e062ae..0acd8edd999 100644
--- a/Snap_rounding_2/doc_tex/Snap_rounding_2_ref/intro.tex
+++ b/Snap_rounding_2/doc_tex/Snap_rounding_2_ref/intro.tex
@@ -75,7 +75,7 @@ container of the output polylines. Since a polyline is composed of a
 sequence of points, a polyline is a container itself.  The fifth
 parameter determines whether to apply ISR or SR.
 
-The forth parameter denotes the pixel size $w$. The plane will be
+The fourth parameter denotes the pixel size $w$. The plane will be
 tiled with square pixels of width $w$ such that the origin is the
 center of a pixel. The sixth parameter denotes the output
 representation. If the value of the sixth parameter is {\it true\/}