Dividing a Line with Compass Only
While working on an article today, I wanted to share a method I used. What ancient geometry achieved with just a compass and a straightedge is truly amazing. I’m going to show you how you can use a compass to divide a line into any number of equal parts. This video shows the method of constructing equal segments on a line by only using compass operations. Here, you can see that there is a pattern in the number of required compass operations. For example, if you need to divide the distance by 3, you need 13 circles (or compass operations). This reveals a simple equation of
c = 2 * n + 3
Here, n is the desired number of segments and c is the number of required compass operations. Today, I learnt that these kind of compass-only constructions are also called Mohr-Mascheroni constructions. Because in 1797, Mascheroni (after Mohr) proved that all compass-straightedge (Euclidean or geometric) constructions are possible with a compass only.






