In this final section, students have the opportunity to apply their thinking from throughout the unit. As this is a short section followed by an End-of-Unit Assessment, there are no section goals or checkpoint questions. All lessons in this section are optional.

This section connects the geometric understanding of dilations and similar triangles with the algebraic understanding of slope and equations of a line.

In this section, students study scaled copies of pictures and plane figures. Students begin by looking at copies of a picture, some of which are to scale and some of which are not. They use their own words to describe what differentiates scaled and non-scaled copies of a picture. As the section progresses, students learn that a scaled copy is...

In this section, students learn about scale drawings and use them to solve problems. They see that the principles and strategies that they used to reason about scaled copies of figures can be used with scale drawings.

At first, students work with scales that involve units (for example, “1 cm represents 10 km”). They interpret and draw maps and floor...

Work in this section builds on the concept of scaled copies to introduce a new transformation—dilations. Students begin by sorting rectangles and notice that rectangles that are scaled copies of one another can be arranged so that the diagonal of the largest rectangle contains the diagonals of the smaller rectangles.

Next, students are introduced to the circular grid and draw...