Use this feature to dimension the angle between two lines.
Using the Function:
Select Two Lines from the Detail>Angular Dimension submenu.
Select the first line.
Select the second line. To make it easier to identify the angle you want to dimension, the program draws temporary dashed lines that extend to the limits of the screen along the selected lines. The intersecting lines define four angles for dimensioning.
Select inside the angle you want to dimension. The temporary dashed lines disappear.
Specify whether you want to dimension the inner or outer angle.