Show/Hide Rulers 

    If the horizontal and vertical page rulers are currently being 
 displayed then the second item in the Page menu is displayed as Hide 
 Rulers. Selecting this item removes the rulers from the document 
 layout window. If the horizontal and vertical page rulers are not being 
 displayed then the second item in the Page menu is displayed as Show 
 Rulers. Selecting this item displays the rulers in the document layout 
 window.
    The measurement units reflected in the rulers are set through the
 Document Setup dialog box  when the document is created and can 
 be changed through the Ruler Settings menu option (Edit menu) .
    You can change ruler settings alsoking the upper left corner 
 (intersection) of the rulers, with the Option key being pressed.  When 
 you do so,the type of unit-measurment is displayed.  The following 
 units are available: inches, picas, points, and centimeters.