Mac PDF Measure It 1.01   
by Traction Software   

Mac PDF Measure It is an Acrobat plug-in tool, it enables accurate measurement of the distance and angle between two points on a page. To measure a distance, click anywhere on a PDF page to set a reference point, then click again in the same page to set a measure point, Measurements include horizontal, vertical, distance and angle degrees, changeable size & colored crosshairs are placed over the page at both points, crosshairs can also be finely adjusted by pressing the arrow keys.
Measurements are shown in either points, picas, inches, feet, yards, centimeters, millimeters & meters.