You should see rulers (bars with numbers) on the upper and left-hand side of the workspace. These show the size of a selected object on the page (see the gray double lines, highlighted in the illustration). When no object is selected, they show the location of the mouse pointer, which helps to accurately position drawing objects. You can also use the rulers to manage object handles and guide lines, making it easier to position objects. The page margins in the drawing area are also represented on the rulers. You can change the margins directly on the rulers by dragging them with the mouse.
Rulers show the size of the selected object
To modify the units of measurement of the rulers, right-click on one of the rulers. The two rulers can have different units.