Polygons and Desmos #teach180

So Joel (@joelbezaire) is an amazing human. If you don’t already follow him, go fix that right now and then continue reading. He shared, at some point maybe this past summer, two Desmos AB activities for investigating Polygon Interior Angle Sums and Exterior Angle Sums. I LOVED them!

(Link To Interior Angle: https://teacher.desmos.com/activitybuilder/custom/5b75d8d696a0ad0aefe7f3ff)

So I did what any good teacher does, I adapted them for use in my classroom-aka I made a notes sheet to go with the AB so students could record their thoughts and findings.

Today went amazingly well with the interior angle problem!

Oh, and we had a “snowball” fight for switching papers to check our hypothesis on the warm up.


First Big Proof Assessment #Teach180

Today was the official start of our two day proof based assessment for congruent triangles and CPCTC proofs. The students were nervous on Tuesday, and I could tell they were going to need a confidence boost, so I thought about a tweet from Howie I saw on twitter. He had students talk about a test w/o pencils, before a test and it has had good results from what I’ve seen in the #MTBoS people that have adopted it. So I did my version:

Students worked for 30 minutes, then they got 10 minutes to talk to a peer w/o a pencil about all the proofs they’d done at that point. Less than a minute into talking I could see students relaxing, feeling more confident in their work, and giving thoughtful feedback to their peers. #worthit


Flappers 2.0 #Teach180

Geometry has a LOT of theorems. There’s no sugarcoating it, that’s a lot of memorization. And if I ask students to memorize them, then I can either:

  • Ask not-so-interesting questions on assessments so I know if they memorized the theorems (MC/Matching) or
  • Give them the theories after we prove them on assessments so I’m free to ask bigger/more thoughtful questions.

I go with the second option. So we make flappers to contain all the theorems for the year and today we added 4 sections:

Sigh #Teach180

I dont have much inspiring to say today. Geometry did good work with a review of Triangle congruency short cuts and a review of vertical angles and parallel lines with transversal properties.

My AFM babies are giving me grey hair. I need a better system for holding them accountable for missed work due to college auditions (for context I have had kids out for a week+). What I’m doing now isn’t working and it’s just giving me (and then) the blues.

Will keep on pondering of better plans. As always this career teaches me constantly my husband’s favorite Marine Corps quote:

Adapt and overcome.

Geometry Arguments #Teach180

Today we did a MathShell formative assessment on evaluating Triangle congruency. The students did a great job thinking through their answers and justifying their thoughts by drawing counter examples.

Their biggest concern was one character was named Ernie in Problem 2 and another was Bert in Problem 3 and how dare the writers separate Bert and Ernie like that!!

The coffee incident #Teach180

Today was a pretty usual school day with the exception of my arrival to campus. In geometry we practiced identifying Triangle congruency shortcuts and had a debate about why we need to agree on one way to read a diagram (so AAS isn’t confused with ASA). In AFM we looked more in-depth at the Venezuela hyperinflation data and I’m looking forward to seeing students final products tomorrow.

But none of that made today hectic. What made today hectic was: pouring rain and coffee.

A primer: they’ve been re-paving all of the roads I take to school for a while now. So there aren’t any reflector things on the road. Combine that with heavy rain and it makes my 30 minute commute stressful.

Because it was raining hard I had to pick the toddler up to run to the car this morning. Somewhere between the door and the car my coffee mug must have opened. When I got to campus and opened my trunk I found a puddle of coffee EVERYWHERE. By some act of the coffee gods the liquid avoided not just my laptop (🙌) but also my grades papers.

My car now smells like a cafe.

The Problem with Modeling Current Events #Teach180

Today in AFM we started contextualizing the modeling task we will be working on for the next week: The Economic Crisis in Venezuela.

I found videos and articles to explain the Geo-political history that got us here, and made points to parallel what’s happening now with all the other times economies have raised and fallen throughout the world (USA, Japan, Hungary, and Germany just to name a few). Today was a helpful moment for students to grasp the severity of the impacts of the hyperinflation.

The plan was context today, next class research prices and see how much food and goods you could afford on the Venezuelan monthly Minimum Wage (~$12)so we could see how that wage changes if inflation continues to rise along its current path.

I ran out of time today to do some research before class started and said, offhandedly, something along the lines of “well as long as nothing drastic happens between now and Thursday we can pick up with the modeling.”

Then I checked twitter:

Well, the good teacher news: my kids are aware of what’s happening in the world.

The bad teacher news I think this announcement will change our predictions on how the economy is changing…

On a related note: sending vibes to the people of Venezuela. I hope that tomorrow’s marches are peaceful.

Discovering Triangle Shortcuts and Breaking Desmos #Teach180

Today in geometry we looked into Triangle congruency shortcuts hat involve combinations of sides and angles. Here is some student work for why the SSA shortcut doesn’t work.

I’m hopeful future-them will remember this day when they’re in PreCal and doing the ambiguous case of Law of Sines.

In AFM I had such grand plans for our third day of modeling with functions. Then the Internet Gods smited us…smote us…what ever the past tense is for smite.

I have no idea what happened. But Desmos wasn’t showing a line of regression for all my students, and a lot of them were getting negative growth factors in regression when it should have been positive.

All and all 23 of my 38 students couldn’t get a regression line to populate. I have some ideas about what could have gone wrong. I plan to test them this weekend. My thoughts are:

  • Maybe because we had 3 regression lines going and all use the letter b that it made Desmos refer to a previous thing?
  • Maybe our schools internet is blocking something
  • The “log mode” option disappeared this week on my app, so maybe there was an update I don’t know about?

Who knows family. I’ll get it figured out cause my next 3 weeks are all Desmos-regression-heavy.

Congruence Shortcut Work #Teach180

Today we formally started to look at Triangle congruency shortcuts in Geometry. We, by the end of class, established the following conjectures:

  • 1 congruent side is not enough to make 2 congruent triangles
  • 2 congruent sides is not enough to make 2 congruent triangles
  • 3 congruent sides always makes congruent triangles
  • Some 2 sides congruent and 1 angle combinations work, but we haven’t found a pattern for when.

Good progress was made with our math family today