Students find points on a set of negative parabolas and find quadratic equations that "best fit" the displayed image. Students problem solve and brainstorm to complete the activity.
Before the Activity
Find and download a picture of McDonald's Arches from their sign or logo. Set the grid in Activity Center to workable steps that fit the needs of your students. (0.5 steps work well)
During the Activity
First, students look at the different quadratic forms using the graphing functions of the TI-73. Use Quick Poll to ask students how variations change the graphing of the function. Once students are comfortable with entering different forms of quadratic equations, load the McDonald's Arches picture into the grid in Activity Center. Next, have your students plot points on one of the arches. Once students have plotted points, remove the image from the background and remove any outliers that do not fit the data. Send the plotted points to student calculators via Navigator and have students find equations that best fit the parabola. Encourage your students to check their work before sending it back to the teacher.
After the Activity
After the activity is completed, use quickpoll to assess possible problems you noticed during graphing. I rewarded the "best-fit" parabola with a McDonald's lunch.