Talk:Geometry for Elementary School/Copying a line segment

What is this? If I need to copy a line segment here is what i would do. Measure the existing line segment AB, go to the point T and with my ruler I draw another line segment of length equal to AB. Why do I have to go through all these circle drawings? Why does my simple solution not work?
 * Good question. The reason is the Greek "rules of the game".
 * See Compass and straightedge constructions
 * The ruler to be used is assumed to be infinite in length, has no markings on it and only one edge, and is known as a straightedge. APH (talk)

I also think this construction method is unnecessary. If all you need is to copy line AB to T at any direction, use a compass to measure the length of AB, draw a circle centerred at T with radius AB. You can have as many lines as you need that are equal to AB, i.e. all lines from T to any point on the circle.

To copy a line with the same direction, simply construct a parallelogram BATC, where AB equals TC. (This takes about three steps.)