Similarity Unit – Part 1

As I enter the world of Common Core for Geometry according to the MDC framework, finding supporting lesson materials has been a challenge.  This is in particular because the curriculum uses transformations as an anchor for many topics.  I have been fortunate to be part of a2i where I have gained a lot of knowledge and curriculum materials.  The unit sample lesson sequences have been a particular help.  That leaves the day to day lessons.  Recently, Lisa Bejarano shared her unit plans and lesson sources for the year so far with a neat unit outline as well.  I decided to try Lisa’s lesson sources out for the Similarity unit. Here is what I found for my self so far.

Photography Faux Pas and the Statue of Liberty lessons had great engagement and discussions around both of the lessons.  I then looked forward and realized that the EngageNY and Khan Academy would both not be an easy fit for my students or technology in the classroom.  I started down a new fork in the road and had a couple of great lessons on dilations.  The first lesson was David Wee’s Everyone Dilates a Triangle.  At this point, my students had a rough understanding of dilations and I wanted to sharpen their skills and had arguably one of my best lessons of the year:

Create a Dilation Poster

I assigned each group to make a poster based on their knowledge of dilations and a series of videos.  I created 4 videos that I embedded to loop in an Keynote presentation.  Each video had a few questions designed to deepen understanding of a part of dilation understanding.  At the end of the videos, each group put together a poster collating all of their ideas on one dilation poster. While this was a great lesson, I spent 3 days on it and could have organized it better.  Regardless of the organization, I will definitely stick with the  idea for summarizing concepts.  Students were really engaged and had great conversations.

I have completed the dilation portion of the unit and realized that the Statue of Liberty lesson would fit better as a bridge between dilations and similarity proofs.

This has been my best unit of the year so far and far better than last year.  The resources from Lisa are amazing and a2i as well.  I am lucky to have access to both.


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