8-3/4 minute video on drawing a pentagon with a given side length and a protractor.
The above video describes the process of drawing a pentagon with a given side length, using an extra tool: the protractor.
I describe the math behind the angles found in a pentagon. You do not need to memorize the math, though the information is there so you know how the process was created. If you use a protractor for making a pentagon, you do need to know this angle: 108 degrees.
The concept is precise, though execution is often not perfect because of several factors. The first is that pencils and compasses need to be sharp and capable of fine lines. The second is that small inaccuracies in alignment and compass adjustments accumulate into larger errors; this is called cumulative error. A third factor in error is not aligning the protractor to the given line properly, and/or not aligning the mark to 108 degrees.
The tools used are:
straight edge pencil compass protractor
