SWBAT understand that a two-dimensional figure is similar to another if the second can be obtained from the first by a sequence of rotations, reflections, translations, and dilations.

Students try their hand at dilating and then transforming a given figure on a coordinate plane.

8 minutes

For Warm Up today, students will spend 4 minutes sharing their answers from the previous day's lesson closure. I want students to share with partners first so that they have the opportunity to verbally rehearse their thinking which will increase their comfort level if selected to respond to the prompts.

Once the timer expires, I select randomly students to share their answers with the class. I then facilitate discussion until the class reaches consensus about who were Flip family members and why.

I then move to the day's learning objective and review the week's new academic vocabulary (introduced in the previous day's lesson): dilation.

Shapes On A Plane Day 5.notebook (Smart Notebook file)

Shapes On A Plane Day 5 Notebook.pdf (PDF of Notebook file)

2 minutes

Next, I introduce today's Learning Objective & Key Vocabulary. I want to activate memories of yesterday's key vocabulary as I have included it in today's Work Time assignment.

20 minutes

I have broken Work Time into two parts today. For Work Time Part I, I ask students to again plot Pip Flip (from the previous day's lesson from The Missing Link Curriclum, Flip Family Lesson) on their coordinate_plane. I then ask them to dilate and then transform Pip so that he appears somewhere else on the coordinate plane. Students record their coordinates for their dilated Pip in their journals.

Once the 20-minute Work Time expires, I move students to the next part of the lesson.

10 minutes

For Work Time Part II, I ask students to now prove that their original Pip and their transformed Pip are similar by using a variety of tool including

- rulers
- angle rules/protractors
- grid paper
- coordinate points charts
- transparencies/markers

By allowing a variety of tools, I am expanding opportunities for students to have success with this part of the lesson. While stronger students will likely use the rulers and protractors, less confident students may choose to use the transparencies and trace their figures to prove their similarity.

5 minutes

For lesson closure today, I choose Consensus Building as a strategy because I want students to come to consensus about what specific features make two figures similar. While congruence is typically a concept easily understood, similarity sometimes poses a challenge because the figures no long appear congruent. Students must use evidence to justify similarity.

Once the class has come to consensus, I transfer their ideas to an "anchor chart" which I post on the wall where it remains for future reference by students.

Next Lesson