diff --git a/Principal_component_analysis/include/CGAL/PCA_util_Eigen.h b/Principal_component_analysis/include/CGAL/PCA_util_Eigen.h
index 09cac7bd6cb..45efdd2cff0 100644
--- a/Principal_component_analysis/include/CGAL/PCA_util_Eigen.h
+++ b/Principal_component_analysis/include/CGAL/PCA_util_Eigen.h
@@ -575,7 +575,8 @@ assemble_covariance_matrix_3(InputIterator first,
     transformation << t[0].x(), t[1].x(), 0.0, 
                       t[0].y(), t[1].y(), 0.0,
                       t[0].z(), t[1].z(), 1.0;
-    FT length = std::sqrt(t.squared_length());
+    using std::sqrt;
+    FT length = sqrt(t.squared_length());
 
     // skip zero measure primitives
     if(length == (FT)0.0)
diff --git a/Principal_component_analysis_LGPL/include/CGAL/centroid.h b/Principal_component_analysis_LGPL/include/CGAL/centroid.h
index 0db7126ebcc..019a9a2a2be 100644
--- a/Principal_component_analysis_LGPL/include/CGAL/centroid.h
+++ b/Principal_component_analysis_LGPL/include/CGAL/centroid.h
@@ -449,7 +449,8 @@ centroid(InputIterator begin,
       it++)
   {
     const Segment& s = *it;
-    FT length = std::sqrt(s.squared_length());
+    using std::sqrt;
+    FT length = sqrt(s.squared_length());
     Point c = CGAL::midpoint(s.source(),s.target());
     // Point c = K().construct_midpoint_3_object()(s[0],s[1]);
     //Point c = Point((s[0][0] + s[1][0])/2.0, (s[0][1] + s[1][1])/2.0, (s[0][2] + s[1][2])/2.0);