The Undefined Notions
Before we can talk about objects or concepts in geometry, we need actual material to work with. Without them, we're no better than a lumberjack without any lumber. Would that just make him a jack?W...
Numbers in Geometry
Addition and subtraction aren't just for numbers anymore. As it turns out, we can add and subtract segments and angles. In fact, the ancient Greeks were so fond of geometry that they defined their...
Dimensions and Extensions
So far everything we've been doing has been flat, boring, two-dimensional. It's time to add some depth to things (and to show how hard it is to draw depth on a sheet of paper or a computer screen...