About this video
A social media account's follower count is plotted against time. Slope, rise over run, tells you how fast the count is growing, so the steepest part of the graph marks the fastest growth. The video shows how to compare slopes by eye, including a big jump with no scale, and concludes the steepest interval is between two and three months.
You'll be able to
- read a line graph by identifying what each axis measures
- explain slope as rise over run in a real-world context
- identify the interval with the greatest rate of change on a graph
Key words
- Slope
- Rise over run, which measures how much the output changes for each step in time.
- Rise
- The change in the vertical value, here the number of followers.
- Run
- The change in the horizontal value, here time in months.
- Rate of change
- How quickly a quantity increases or decreases over time.
Transcript
- [Instructor] Nayeli created a social media account for her company, and she tracks the account's number of followers on the graph below. On what interval did the number of followers increase the fastest? Pause this video and see if you can figure that out. All right, so when we look at this graph, the horizontal axis is time, the vertical axis is number of followers.
So, really, what we're looking for, the interval where we have the highest slope. So we can just eyeball it right over here, and we can see that this slope right over here is higher than this slope. And just as a reminder, slope is rise over run. So every time you increment your time by one month, how much did you rise?
Clearly, we rose more over this interval than we did over this interval for a month. But then this one over here is looking really interesting, because just in one month, we don't have a scale on the number of followers, but it's clear we got a very large rise.
And so the slope is the largest right over here, larger than any other point on this graph. So that's between two and three months. So I am liking this choice right over here.
Video © Khan Academy, used under CC BY-NC-SA. Watch on Khan Academy. Puzzicle is not affiliated with Khan Academy.