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### Quick Tangents and Perpendiculars...

posted Mar 17, 2011, 11:41 AM by Reinaldo Togores Fernández   [ updated Nov 22, 2012, 11:10 AM ]
The solution of many geometric problems requires tracing perpendiculars or tangents to certain objects. I often see my students going through the laborious process of drawing a line and then rotating/copying it 90 degrees and even sometimes moving it to the point where the perpendicular must lie.
The method I show in the video is the one I advise them to use, since it is not enough to solve the problem, but it must be done quickly and efficiently.

## Perpendiculars.

It consists in using the Construction Line (XLINE). After calling the XLINE command we type PER to indicate that the next selection shall be made using the PERpendicular object snap, and then we select the object to which the XLINE should be perpendicular to. From that moment on, every time we select a new point a Construction Line perpendicular to the object will be created at the point clicked. Particularly interesting cases are those in which the selected object is a polyline or spline, as shown in the video below.

## Tangents.

Just as in the previous example, except that in this case we type TAN and the selected object must be an arc, a circle or a spline. The video is self explanatory.