The Line Segment constructions allow you to quickly and accurately dived a line into equal parts or a desired ratio.  The equal segment construction may look familiar to those of you have used the ruler trick to divide a board equally.  These constructions may look a little involved but are quickly executed once you are familiar with them.  Allowing you to quickly divide a length as you desire.

Greg Merritt

Jim Tolpin, one of the authors of the book “By Hand &Eye” has posted animated clips of geometric constructions on his YouTube channel.

There is also information and animations on the Math Open Reference website.