Continue Dimension
The Continue Dimension 
tool creates
a chain of dimensions in which each new dimension continues from the end of the
previous one, forming a continuous dimension string.
Creating a continue dimension
-
Select the Continue Dimension tool.
-
Pick the first dimension point. Hold Ctrl to pick an aligned reference line, or Shift to pick a perpendicular reference line.
-
Pick the second dimension point. Hold Shift to set the dimension angle.
-
Move the mouse to position the dimension line, then click to place it.
Repeat the command to continue the chain from the last point.
The Text, Tolerance, and Angle input boxes let you override the dimension text, add a tolerance, and set the angle of the dimension line. See the section overview for the options shared by all dimension tools.