how do i construct a perpendicular line at the end of a given line?

Question

the subject is td technical drawing

Answer 1

If you had a complete line, and wanted to construct a perpendicular to a point, you would first mark off an equal distance along the line on either side of the point (using a compass).

You would then lengthen your compass and put it at one of the points you just constructed. Draw an arc to one side of the line. Do the same with the other point so that the two arcs intersect. Connecting this point to the original point with a straight-edge will form a perpendicular line.

So the only thing you need to do in your case is to extend your line beyond the given point so you can then create the perpendicular line. Later you can erase the line extension.

Another method is to mark off 5 little equal marks on your line using the compass. Now expand your compass to be equal to 3 of these marks. Draw an arc from the end point of the line (length 3). Now expand your compass to be equal to 5 of these marks. From the *4th* mark, draw another arc intersecting the first. This will make a 3-4-5 triangle which is a right triangle. Connect this point back to the endpoint to make a perpendicular line.