standard_description: Know that numbers that are not rational are called irrational. Understand informally that every number has a decimal expansion; for rational numbers show that the decimal expansion repeats eventually, and convert a decimal expansion which repeats eventually into a rational number.
problem_activity: Sylvia bikes home along a straight road from her friend’s house, a distance of 8 miles. The graph shows her journey:
[IMG]
Describe what may have happened. Be sure to include details about her pace, points that indicate a change in action, and where she starts and stops.
Are all sections of the graph realistic? Explain your reasoning.


aligns: no