# Activities

• • • ##### Subject Area

• Math: Algebra I: Linear Functions

• ##### Author 9-12

• ##### Device
• TI-92 Plus / Voyage™ 200
• ##### Other Materials
This is Activity 2 from the EXPLORATIONS Book:
Discovering Math on the Voyage 200.
• ##### Report an Issue

Getting Down to Basics

#### Activity Overview

In this activity, students explore linear equation models for real-life situations. They learn to find a linear equation when two pairs of related points are on a line.

#### Before the Activity

• See the attached PDF file for detailed instructions for this activity
• Print pages 7 - 13 from the attached PDF file for your class
• #### During the Activity

Distribute the pages to the class.

• Use the values for the freezing temperature of water (32° F, 0° C) and the boiling temperature of water (212° F, 100° C) as data points
• Use the data points to calculate the slope of the linear model that can be used to find the conversion formula (Fahrenheit and Celsius readings)
• Divide the change in the y-value and in x-value to find rate of change and thus the slope
• Substitute one of the ordered pairs into the equation y = mx + b, and find the y-intercept
• Use values of m and b to write the equation for converting temperature in Celsius (y-value) to Fahrenheit (x-values)

• Given coordinates of two points on a line, use the slope formula m = (y2 - y1)/(x2 - x1) to find the slope m
• Find the y-intercept
• Write the slope intercept form of the equation

• Write a simple program on the Voyage 200 PLT to find a linear model for any two points

• Solve real world problems using linear models expressed in slope-intercept form
• #### After the Activity

Review student results:

• As a class, discuss questions that appeared to be more challenging
• Re-teach concepts as necessary