Index: src/sp-ellipse.cpp
===================================================================
--- src/sp-ellipse.cpp	(revision 22539)
+++ src/sp-ellipse.cpp	(working copy)
@@ -893,10 +893,11 @@
     ge->rx.computed = rx;
     ge->ry.computed = ry;
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    // those pref values are in degrees, while we want radians
     if (prefs->getDouble("/tools/shapes/arc/start", 0.0) != 0)
-        ge->start = prefs->getDouble("/tools/shapes/arc/start", 0.0);
+        ge->start = prefs->getDouble("/tools/shapes/arc/start", 0.0) * M_PI / 180;
     if (prefs->getDouble("/tools/shapes/arc/end", 0.0) != 0)
-        ge->end = prefs->getDouble("/tools/shapes/arc/end", 0.0);
+        ge->end = prefs->getDouble("/tools/shapes/arc/end", 0.0) * M_PI / 180;
     if (!prefs->getBool("/tools/shapes/arc/open"))
         ge->closed = 1;
     else
Index: src/widgets/toolbox.cpp
===================================================================
--- src/widgets/toolbox.cpp	(revision 22539)
+++ src/widgets/toolbox.cpp	(working copy)
@@ -4929,7 +4929,7 @@
 
     if (sp_document_get_undo_sensitive(sp_desktop_document(desktop))) {
         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
-        prefs->setDouble(Glib::ustring("/tools/shapes/arc") + value_name, (adj->value * M_PI)/ 180);
+        prefs->setDouble(Glib::ustring("/tools/shapes/arc/") + value_name, adj->value);
     }
 
     // quit if run by the attr_changed listener