## Chapter 17

### Part 1: Home and School Investigation

Send the Letter to Family (PDF file) home with each child. Once each of the children has brought in the drawing of the room he or she measured and its recorded measurement, have the children share their pictures. Talk with children about how they measured their rooms and the measurements they recorded. A good time to do this activity is after Lesson 6 on perimeter.

### Part 2: Be an Investigator

A good time to do this investigation is after Lesson 6 on perimeter.

#### Materials

- Investigator Worksheet (PDF file) for each group of two children
- rulers, yardsticks

#### Introducing the Investigation

Write the word **perimeter** on the board and ask the children what it means. Tell them that they are going to use rulers to find the measurement in inches around different objects. Show them the chart on the Investigator Worksheet. Point out that the first column tells them what to measure. Read through the list of what they will measure and point out that the last object is their choice. Show children that the second column is where they will put their guesses or estimates of how many inches the perimeter will be. Tell children that after they measure the actual perimeter they will write the measures in the third column.

Put each child with a partner and give each pair an Investigator Worksheet, a ruler, and/or a yardstick.

#### Doing the Investigation

Children may not understand that some objects have equal sides. They will need to find the measure of each side of an object and then add all the measures together to find the perimeter.

Observe children as they measure to make sure they are lining up the ruler or yardstick correctly. If not, model correct ruler or yardstick placement for children.

#### Extending the Investigation

Work together as a class to measure the perimeter of your classroom using a larger unit of measure, such as a yard. First, have each child make a guess or estimate of what they think the perimeter will be.