# Reflecting on: Kisilev's Geometry

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One of my goals for the summer was to review geometry, so I decided to speed read Kisilev's Geometry. My work has always involved a good bit of trigonometry, but over the past year or so the amount of geometry I use has only increased. As a bonus, I also just enjoy geometry.

While reading these books, I wanted to take notes that would be helpful in the future. I am a big fan of zettelkasten and after about two years of working on it, I thought it would be helpful to add some geometry notes. It also matched the time commitment I wanted to spend on these books. I wasn't interested in working through every single proof. Instead I wanted to set up my notes so I could easily find what I want in the future.

The books are separated by planar and solid geometry, but they're meant to be read together. They cover the contents of a high school geometry course, with a little coverage of non-Euclidean geometry in the last chapter of book II. There are some terminologies and abbreviations that are no longer common, such as using *d* to represent a 90 degree angle. I didn't like this at first, but now I find myself using it as a useful shorthand.

I worked through them fairly quickly since I was already familiar with everything, but I did enjoy the connections I made while writing notes. My next step in this project is to go through and consolidate all my notes, adding cross references, tags, etc. For the next batch of notes, I plan on speed reading The Method of Coordinates, Functions and Graphs, and Trigonometry, all by Gelfand. They have been on my bookshelf for too long and I think their notes will overlap fairly well with what I added from Kisilev.