The Measure group contains the measurement and calibrate tools. It is accessed by clicking Measure on the Menu bar.
Calibrate
Calibrate: Calibrates the document's scale to allow accurate measurements to be taken.
Linear
Length (SHIFT+ALT+L): Calculates a singular linear measurement.
Perimeter
Perimeter (SHIFT+ALT+P): Calculates the length of all the sides of a given shape or multi-segment line.
Area
Area (SHIFT+ALT+A): Calculates the area of a simple rectangle or of an irregular, polygonal shape.
Volume
Volume (SHIFT+ALT+V): Calculates the volume of an area with a defined depth.
Count
Count (SHIFT+ALT+C): Places a markup for each mouse click, associating a running total of counts with each markup as it is placed.
Radius (SHIFT+ALT+U): Measures the radius a circle, defined center-out.