Last spring, I placed equations of circles after distance between 2 points. The idea came from a mini-investigation in my Discovering Geometry book (formerly Key Curriculum, now Kendall Hunt).

Earlier in the semester a new colleague shared the success her students experienced with the Formative Assessment Lesson Equations of Circles 1. I decided to use this lesson…

In my early geometry class yesterday, we literally stared at circles. It felt like a wasted class. No matter what example I referred back to, or what question I asked, it just didn’t work. Thankfully, I had planning immediately following and I was able to reflect very quickly. For my last geometry class of the day, I adjusted my sequence of leading examples. Reviewing our previous work from last week.

The remainder of the lesson went smoothly. A quick white-board quiz at the beginning of class today allowed me to address some small errors. Once again, I had them create their own notes/examples in their INBs. Yes, a few are still lacking, but the majority are very thorough in what they are including. Asking questions about specific what-ifs, like one student brought up none of our examples today had a center located at the origin, so I asked the class if they could remind her. Several went on to include a similar example on their page.

The lesson continued with a collaborative pair. They were given 12 equations to sort by center and radius. There were 4 blank blocks in their grid that required them to create their own equations. At the beginning, some were “cheating” so I stopped them to remind them 1 person picked a card, explained why they were placing it, the other person had to agree and understand before taking their turn. They are getting better at disagreeing and telling why when their partner is making a mistake.

Their assignment was to create an artistic picture incorporating 5 different circles and listing their equations on the back. Short, sweet, simple. Can’t wait to see them.