## Finding the Measure of Segments

### Johnny WolfeSanta Rosa District Schools

#### Description

This lesson uses the betweenness property, segment addition property, and distance formula to determine segment lengths.

#### Objectives

Understands and explains the effects of addition, subtraction, multiplication and division on real numbers, including square roots, exponents, and appropriate inverse relationships.

Using a rectangular coordinate system (graph), applies and algebraically verifies properties of two-and three- dimensional figures, including distance, midpoint, slope, parallelism, and perpendicularity.

#### Materials

-Overhead transparencies (if examples are to be worked on overhead) for Finding the Measure of Segments (See Associated File)
-Finding the Measure of Segments Examples (See Associated File)
-Finding the Measure of Segments Worksheet (See Associated File)
-Finding the Measure of Segments Checklist (See Associated File)

#### Preparations

1. Prepare transparencies (if teacher uses overhead) for Finding the Measure of Segments Examples. (See Associated File)
2. Have marking pens available (for overhead).
3. Have Finding the Measure of Segments Examples (See Associated File) prepared and ready to demonstrate to students.
4. Have enough copies of Finding the Measure of Segments Worksheet (See Associated File) for each student.
5. Have enough copies of Finding the Measure of Segments Checklist (See Associated File) for each student.

#### Procedures

Prior Knowledge: Students should be familiar with basic operation skills such as addition, subtraction, multiplication, division, fractions, and decimals.
Note: This lesson does not address three-dimensional figures, midpoint, slope, parallelism, and perpendicularity. Nor does it address matrices.

1. Introduce students to the term “betweenness.” Give students examples of betweenness. (See #1 on Finding the Measure of Segments Examples) Answer student questions and comments.

2. Discuss Ruler Postulate. (See #2 on Finding the Measure of Segments Examples) Answer student questions and comments.

3. Discuss distance between points on a number line. (See #3 on Finding the Measure of Segments Examples) Go over samples. Answer student questions and comments.

4. Work #4 Example. (See Finding the Measure of Segments Examples) Answer student questions and comments.

5. Discuss Segment Addition Postulate. (See #5 on Finding the Measure of Segments Examples) Answer student questions and comments.

6. Work #6 Example. (See Finding the Measure of Segments Examples) Answer student questions and comments.

7. Work #7 Example. (See Finding the Measure of Segments Examples) Answer student questions and comments.

8. Discuss Distance Formula. (See #8 on Finding the Measure of Segments Examples) Answer student questions and comments.

9. Work #9 Example. (See Finding the Measure of Segments Examples) Answer student questions and comments.

10. Work #10 Example. (See Finding the Measure of Segments Examples) Answer student questions and comments.

11. Distribute Finding the Measure of Segments Worksheet. (See Associated File)

12. Distribute Finding the Measure of Segments Checklist. (See Associated File) Describe what constitutes an A, B, C, D, and F in the Checklist.

13. The students write their responses on the worksheet.

14. The teacher moves from student to student observing their work and lending assistance.

#### Assessments

The student worksheet is collected and scored according to the Finding the Measure of Segments Worksheet Key and Checklist. (See Associated File)

#### Extensions

Have the students draw a diagram of their classroom on a coordinate grid. The students plot various items on the grid (door, teacher’s desk, cabinets, etc). Then they determine the distance between these items using the distance formula.