You are driving along the open highway on a cross-country road trip, cruising at a steady speed of $60$ miles per hour. **What is the slope of the line representing this relationship?** The slope is [[☃ input-number 1]] . **Graph the proportional relationship $d=60t\,$ that expresses your distance traveled $d$ (in miles) in terms of time $t$ (in hours) since you started going $60\, \text{mph}$. ** [[☃ interactive-graph 1]]