How to mark certain distance on a line?

[arulmozhi]

How to draw a perpendicual line from a point of another line at some specified distance?

[eldon]

There are probably many ways of constructing a line perpendicular to another, but one way is to use Polar Tracking.

 

Make sure that the settings for Polar Tracking have the Polar Angle Settings to include 90° and the Polar Angle measurement is set to Relative to last segment.

 

Then at the end of your line, draw a perpendicular line. Then move that line with the base point set at the end of the original line, and just pull it along the line and enter the distance from the keyboard.

[nukecad]

As eldon says there are many ways of doing this.

 

I would suggedt that you take a look in your AutoCAD help at the XLINE command and its options (Horizontal, Vertical, Angled, Offset, Perpendicular, etc).