xrandr 
Screen 0: minimum 8 x 8, current 1366 x 768, maximum 32767 x 32767
VGA1 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 885mm x 498mm
   1360x768i    120.03 +
   1280x1024     75.02    60.02  
   1360x768      59.80* 
   1280x800      59.91  
   1024x768      75.08    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32    56.25  
   640x480       75.00    72.81    66.67    60.00    59.94  
   720x400       70.08