## Lesson: Finding the Length of a Line

Introducing the Concept

Finding the length of a line segment by subtracting its coordinates is an important skill for your students to master now. In the next few years, they will learn more about graphing lines. To do that, they need to have a solid understanding of these basic concepts.

Your students have probably had experience with number lines at prior grade levels. Use that experience to introduce finding length on a grid.

**Materials:** poster paper or a transparency and overhead projector for demonstration; straightedge

**Preparation:** Draw a coordinate grid on poster paper or a transparency. Label the *x-* and *y-axes* from 0 through 10.

**Prerequisite Skills and Concepts:** Students need to be very familiar with locating ordered pairs on a grid.