Think About the Process Why is a data point with an x-coordinate of 0 a good point to use when creating a trend line for a data set? The graph shows the altitude of a weather balloon over time. The trend line passes through the points (0,402) and (10,484). Write the equation of a trend line for the data shown in the graph. After how many minutes is the balloon at an altitude of 459.4 feet above sea level?