# Lesson 5

Scaling and Unscaling

### Lesson Narrative

In this lesson, students practice working with areas of scaled figures, connecting them to cross sections and encountering a common misconception.

Then, they create a graph representing $$y=\sqrt{x}$$ and use it to answer questions about a situation. They analyze the shape of the graph to better understand the relationship between an area and the scale factor needed to achieve it.

When students consider two arguments (one of which includes a common misconception) and decide which is correct, they are critiquing the reasoning of others (MP3).

### Learning Goals

Teacher Facing

• Describe (using words and other representations) the relationships between scale factors and areas using square root graphs and calculations.

### Student Facing

• Let’s examine the relationships between areas of dilated figures and scale factors.

### Required Preparation

Devices are required for the digital version of the activity Graphing Areas and Scale Factors.

### Student Facing

• I can use square root graphs and do calculations to interpret the relationships between scale factors and areas.