Perpendicular

Creates a line perpendicular to an existing line.
Tip: This tool creates a line from an existing line. To create a perpendicular line to a line, you can use the "J" SEKE (see Running and Local Snaps.

1. Select an existing line. 
   
2. Type in a Length. Then click Tab. 
   
3. Select a another point to set the length of the perpendicular line.
   

Local menu option: 
Limit to Segment: The perpendicular line cannot extend past the endpoints of the existing line. 

Tip: To draw a line perpendicular to an arc or circle, draw a single Line from the center of the arc or circle to its destination, then trim the line.