# Activities

• • • ##### Subject Area

• Math: Algebra I: Linear Functions

• ##### Author 6-8
9-12

45 Minutes

• ##### Device
• TI-Nspire™
• TI-Nspire™ CAS
• ##### Software

TI-Nspire™
TI-Nspire™ CAS

## How are the Slopes of Perpendicular Lines Related?

#### Activity Overview

This activity allows students to discover that the slopes of perpendicular lines are negative reciprocals of one another. Students construct perpendicular lines of given lines and then create and label two points on each line. They then use a calculator page to calculate the slope of the lines using the difference in y-coordinates divided by the difference in x-coordinates, (y2-y1)/(x2-x1).

#### Before the Activity

Students should be familiar with the meaning of slope and how to find the slope of a line using: (y2-y1)/(x2-x1)

#### During the Activity

Students construct perpendicular lines and points and then use the calculator page to calculate the slopes of the lines. After analyzing the slopes students should discover that the slopes of perpendicular lines are negative reciprocals of one another.