Unit 2, Lesson 4
Dilations on a Square Grid
Grade 8
Preparation
Lesson Narrative
In this lesson, students apply dilations to polygons on a grid, both with and without coordinates. The grid offers a way of measuring distances between points, especially points that lie at the intersection of grid lines.
Students begin by estimating scale factors for dilations of points without a grid. Next, they perform dilations on a grid and use the structure of the grid to determine distances (MP7). Then students perform a card sort where they match images and descriptions of dilations that are performed in the coordinate plane, allowing students to develop language for precisely communicating figures and their images under dilations (MP6).
- Create a dilation of a polygon on a square grid given a scale factor and center of dilation.
- Identify the image of a figure on a coordinate grid given a scale factor and center of dilation.
Let’s dilate figures on a square grid.
Required Preparation
Provide access to geometry toolkits.
Provide access to geometry toolkits.