# VIDEO: Algebra Applications: Variables and Equations, Segment 3: River Ratios.

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.

This is part of a collection of videos from the Algebra Applications video series on the topic of Variables and Equations.

## Video Transcripts

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Common Core Standards CCSS.MATH.CONTENT.6.EE.B.7, CCSS.MATH.CONTENT.6.RP.A.1, CCSS.MATH.CONTENT.7.RP.A.1 10.20 minutes 6 - 8 Algebra     • Expressions, Equations, and Inequalities         • Applications of Equations and Inequalities         • Variables and Unknowns     • The Language of Math         • Variable Expressions 2011 algebra, variables, equations, ratios, rivers, meander ratio, geology, circular arcs