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Variables and Equations. In this episode of Algebra Applications, two real-world explorations are developed:

- Biology. Honey bees not only produce a tasty treat, they also help pollinate flowering plants that provide much of the food throughout the world. So, when in 2006 bee colonies started dying out, scientists recognized a serious problem. Analyzing statistics from honey bee production allows for a mathematical analysis of the so-called Colony Collapse Disorder. Key math concepts covered include variables, equations, formulas, ratios and proportions, and box and whisker plots. Students use the Lists and Spreadsheets, Calculator, and Statistics features of the TI-Nspire.

- Geology. Why do rivers meander instead of traveling in a straight line? In going from point A to point B, why should a river take the circuitous route it does instead of a direct path? Furthermore, what information can the ratio of the river?s length to its straight-line distance tell us? In this segment the geological forces that account for a river?s motion are explained. In the process, the so-called Meander Ratio is explored. Students construct a mathematical model of a meandering river using the TI-Nspire. Having built the model, students then use it to generate data to find the average of many Meander Ratios. The results show that on average the Meander Ratio is equal to "pi". Key math concepts covered include variables, equations, ratios, geometry and measurement, statistical mean, and data analysis. Students use the Geometry, Lists and Spreadsheets, and Calculator features of the TI-Nspire.

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