To extend and apply the content in the Explain stage of the lesson, students engaged in a Matching Cards activity.  Groups were presented a set of cards that included three representations of linear functions.  The students were given the task to find the tables, equations, and graphs that corresponded to one another.  Groups then shared with the class their method for matching the cards.  After the students practiced applying their knowledge of the three representations, the class moved into exploring a real-world example.  The teacher modeled how to analyze the table representing the workout log of an astronaut over time. Using the table, the teacher showed how to create the equation of the linear function and how to use the equation to graph the astronaut’s progress.  Through the use of the workout log, students could better understand the real-world meanings of the slope, x-intercept, and y-intercept.  Lastly, the students engaged in a mock mission from NASA.  Each group received a unique data set that needed to be analyzed.  For example, some students analyzed water supply while others analyzed oxygen supply.  Other data sets included food supply and calories needed by male and female astronauts.  In their mission, the students needed to represent their data set as a table, equation, and graph.  Next, the students used the three representations to answer questions proposed by NASA and created posters for class presentations.