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Improved Unit on Similar Triangles in Geometry

As mentioned, I have gotten behind on blogging.

Three weeks ago in Geometry, we were discussing similar triangles. Usually when I teach this, I am in a hurry to get to right triangles. I would make the excuse that they did a lot of ratios in pre-algebra, so let's just do similar triangle proofs and get to trig already!

This year I did a few things that made class a lot more engaging. #joyful

1. As mentioned before, I had kids do problem solving in groups using white boards. Five Triangles is a great source of problems to use to mix it up.

2. The Blob - I filed Fawn's golf problem remix away when I first read it last year and I am SO glad that I used it this year.

I followed her script, instructing them to draw a blob somewhere in the rectangle, a point H on one side and a point B on the other. I collected them and made copies. The next day I gave them the copy and gave them the challenge.

Jonathon's wasn't possible with three triangles... I let him draw a new one.
I did more guiding than I had hoped to do. My students aren't used to using measurements that they take themselves (note for their Geometry teacher... oops that's me). Once they figured out that finding the "bounce" point was the objective, most students finished the activity in class. They blogged it for homework.

Several others weren't as lucky. I guided them more after class to solve the system of equations and quadratic formula monster that they ended up with. Despite the work it took, they were super proud when then finished... Like Fawn said, "they owned the problem."

3. Mirror - By blogging about this I am admitting to stealing from CPM... well, hopefully the copyright police don't find me. After watching an awesome webinar from Global Math Department, I filed the "chicken spell" problem away for future use. I love anything that gets them out of their seats, measuring and dancing like a chicken. They had a half a class to take measurements and do calculations. The next day we had kids step to the line to take turns at casting the spell.
Brianna was able to cast the spell on Stauss.
They had to do a summary blog post for homework. To keep it simple, some blog posts are an image of their paper work and a reflection on an in class experience.