Day 151 & 152: Similarity transformation proofs

I waited until the end of the school year for this because I wanted to encourage retention by requiring students to remember basic transformations in addition to applying dilatation which we just worked on. I searched for a good way to help students develop understanding of this. The best description of this standard that I found was Kate Nowak here. In this post she included a link to Khan Academy’s interactive modules. I am not a fan, but these really helped students to see how to prove similarity. I searched for other options and even asked Desmos, but I found this Khan Academy module to be my best option. I set up a “coach” account, then on the first day my students set up accounts, made me their coach, and accessed the module. It took a while for them to get the hang of how it worked. On the second day they will try to get 5 correct in a row, really I just want them to experiment with this some more and develop mastery.

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Sub (Guest Teacher) Plans

I hate having a sub. I hate missing time with my students. My stepdaughter is pregnant and she is due in about a month. I will be there. I know I’m going to have little notice & ill need a sub, so I decided to put together a few days worth of plans over the holiday break. All of it is created by others, none of it is mine, but I thought I’d put it out there anyway as substitute teacher options.

1) Congruent Halves – Fawn Nguyen

This is a challenging task. It may even require 2 class periods. It is self checking, self explanatory and great use of geometry students time. Requires application of congruence and transformations.

2) Intro Proof Axiomatic System – Justin Lanier

This set of activities requires students to use a set of rules to change a word into another word, and then to create their own axiomatic systems. This gets to the heart of geometry in a non intimidating way.

3) Four 4’s & Foxy 5’s

We have done some four 4’s as a warm up and It is clear that students could benefit from a class period (or more) of this. It allows for collaboration and it is easy enough for students to monitor their own progress. The Foxy 5’s I found recently on my idol, Fawn’s blog here.

I am getting each of these copied, and am writing up instructions and keeping them in a convenient place for the next semester. In my 10 years of teaching I have never had emergency lessons ready to go.  Now I have to resist the urge to use them ASAP because they are awesome tasks, and enjoy being prepared for anything!

What do you have your students do when you are gone?

[update 4/1: there is a great collection of sub plan ideas here]

Day 75: Summing up Transformations

I forgot to take pics of our notes today, so hopefully I’ll remember to add some later. I focused on students practicing the formula notation for translations, rotation & refection. Next year I think I will re sequence this unit to start with Mathalicious‘ Face Off, then notes & practice on symmetry & reflections. Then, this project, followed by notes & practice on translations & rotations. Finishing with the Math Assessment project lesson on transformations.

[update 12/20: pic of the transformation notes]

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