All measurement features are located under mainmenu/utilities/measurement. Some of these tools will measure only selected shapes.
A manual or automatic ruler can be used. For a manual ruler click two points with the mouse. To make the ruler permanent hold the control key on the second click. For an automatic measurement in x and y directions to the next edge of a visible shape, hold down the shift key on the first click. You can also make the ruler permanent by pressing the control key. A permanent ruler means that the rule is added to the active layer. With a shift+control key on the first click, you can delete all rulers.
An angle between two or three entered points can be measured. In case only two points are entered, the angle will be calculated to the x-axis. When three points are entered the angle is measured between these three points with the first entered point as the center.
All the elements of the shape under the mouse are measured. The smallest and largest sized elements of the shape are displayed, e.g. for a circle the circumference will be displayed because it is its largest property. The distance from one shape to the clicked shape is also displayed.