## Chapter 21

### Part 1: For the problem in the Teacher's Edition, page 564

Provide the students with a copy of the Activity Page (PDF file).

Bring in magazines and newspaper comic strips that the students can cut up. Ask the students to think about reasons why a person would want to enlarge a picture. Students might suggest such things as:

- to make a billboard
- to make a poster
- to make a larger picture for an album

Tell the students to find pictures they would like to enlarge. Review how to use a grid to do an enlargement.

Answers will vary.

### Part 2: Be an Investigator

A good time to do this investigation is after Lesson 2 on writing and solving equations.

#### Introducing the Investigation

Introduce the investigation by reading aloud the assignment at the top of the first page of the Description of Investigation and Student Report (PDF file), by having one of your students read aloud the assignment, or by having the students read the assignment individually.

Put the students in groups of two to four to work on the investigation.

#### Doing the Investigation

Have the students share some of the statements they have written and prove to the rest of the students that the statement is true or false. You might want to have the students exchange sets of statements about equations and identify true statements and false statements in different sets of statements.

Answers will vary.

#### Student Report

The letter back to Charlene Wong gives students an opportunity to show what they have done.

#### Extending the Investigation

Have the students tell how they can turn each false statement into a true statement.