Fix typos

src/Gui/Quarter/Quarter.cpp

@@ -121,7 +121,7 @@
   \subpage examples
 */
 
-// The subsequent doxygen referenced page/subpages do not exis in the copy of Quarter used within FreeCad.
+// The subsequent doxygen referenced page/subpages do not exist in the copy of Quarter used within FreeCad.
 // To preserve the history and their origin the doxygen commands have been disabled but left in the file.
 // /*!
 //  \page examples More Examples

src/Gui/TaskView/TaskSelectLinkProperty.cpp

@@ -153,7 +153,7 @@ void TaskSelectLinkProperty::activate()
 
 bool TaskSelectLinkProperty::accept()
 {
-    // set the proptery with the selection
+    // set the property with the selection
     sendSelection2Property();
 
     // clear selection and remove gate (return to normal operation)

src/Mod/Sketcher/App/SketchObject.cpp

@@ -7649,7 +7649,7 @@ void SketchObject::rebuildExternalGeometry()
                     double t_min = t_max + 0.5 * M_PI;
 
                     // ON_max = OM(t_max) gives the point, which projected on the sketch plane,
-                    //     becomes the apoapse of the pojected ellipse.
+                    //     becomes the apoapse of the projected ellipse.
                     gp_Vec ON_max = origAxisMajor * cos(t_max) + origAxisMinor * sin(t_max);
                     gp_Vec ON_min = origAxisMajor * cos(t_min) + origAxisMinor * sin(t_min);
                     gp_Vec destAxisMajor = ProjVecOnPlane_UVN(ON_max, sketchPlane);