Final answer:
The phrase "Scale of 3" in Khan Academy refers to the scale or range on the vertical axis of a graph, where each unit represents a value of 3.
Step-by-step explanation:
The phrase "Scale of 3" in Khan Academy when describing graphs refers to the scale or range on the vertical axis of the graph. It means that each unit on the vertical axis represents a value of 3. For example, if the vertical axis has a scale of 3, then a point plotted at a height of 6 on the graph represents a value of 18.