# Virtual Proof Blocks and a Proof Portfolio

I’m trying a couple of new things in the triangle congruence / quadrilateral properties quarter of my geometry class this year.

First, I’m implementing CME Geometry’s methods of analyzing proofs, which uses flowcharts as one way to figure out a proof. I’ve always used flowcharts more as a way to actually present a proof, as done in Discovering Geometry, but I think I like this better.

To help with the flowcharts, I’m planning to use proof blocks, as described at http://www.proofblocks.com and in so many wonderful blogs. These can be cut out and used on white boards or paper to provide visual feedback as to how various definitions and theorems can be connected. I decided to make my own slight variation from arrows. Here are a few of them:

The block in the upper right is the “statement” block, in which you actually  write geometric statements. Those always fall between two of the “reason” blocks. “Given” and “Picture” are the ONLY blocks that can start a line of reasoning.

Here’s a picture of a sample proof using my proof blocks (click to make it larger)

The definitions are double-arrowed so that you can tell they go either way, and are oriented vertically so either the top or bottom can be connected to either side of the mostly-horizontal flowchart.

You can access the entire PowerPoint here, with all of the blocks I made, a few instructions, and a sample proof. Most of the blocks are editable – a few of them got copied as images from my initial Google Drawing attempt and would need to be redone if you want to change them.

I intend to print out a copy for students to use, though I don’t think I’m going to laminate-and-tape them this year. Not enough time. For this year, they will use the printout as reference and draw the blocks. I am also providing them to the students virtually, as a series of images in Microsoft OneNote. Here is a silent screen cast documenting the process I used to work with them virtually in OneNote (on Windows, with tablet PCs). You could probably modify this method to work with may different pieces of software, PowerPoint itself for one, or even something like Google Sheets.