Algebra I: Horizontal and Vertical Lines

Objectives

• Students will identify lines with zero and undefined slope.
• Students will describe, in terms of coordinates, what is special about points on horizontal and vertical lines.
• Students will explain why the slope of a horizontal line is zero and why the slope of a vertical line is undefined.

Vocabulary

• Slope

About the Lesson

The activity involves examining the vertical and horizontal changes when moving from one point to another on a line. As a result, students will:

• Understand that when the vertical change between two points is zero, the slope is zero, and when the horizontal change between two points is zero, the slope is undefined.
• Move points and will observe the line move as well as the vertical and horizontal change.