Geometry & Design: Ratio, Proportion, & Similarity - Definitions
Channel: Plan B Workshop
Date: 2020-03-25

Books V and VI of Euclid's Elements contain the definitions we need to put in place in order to understand the relationship between the concepts of ratio, proportion, and similarity. I introduce those definitions in this tutorial.  Later, we'll use the concepts of ratio, proportion, and similarity to develop techniques for constructing segments whose lengths satisfy prescribed rational relationships. These concepts will also be fundamental to understanding what a sector is, how it works, and why it works.


The tables of contents for books V and VI of the Elements can be found in David E. Joyce's online edition here:
Book V: https://mathcs.clarku.edu/~djoyce/java/elements/bookV/bookV.html#defs
Book VI: https://mathcs.clarku.edu/~djoyce/java/elements/bookVI/bookVI.html#defs