yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Interpreting graphs of proportional relationships | 7th grade | Khan Academy


2m read
·Nov 11, 2024

  • [Instructor] We are told the proportional relationship between the number of hours a business operates and its total cost of electricity is shown in the following graph. All right. Which statements about the graph are true? Choose all answers that apply. So pause this video and see if you can figure this out.

All right, now let's do this together. And before I even look at the choices, let me analyze this a little bit. It is a proportional relationship. So we know that our total cost, let me write it here, our total cost is going to be equal to some constant of proportionality times our number of hours.

And we can even figure out what that constant of proportionality is going to be, because they give us this point A. We know that when our hours are four, so when this is four right over here, our total cost is $120. $120. So what times four is equal to 120? Well, we know that this k must be 30, 'cause 30 times four is 120.

So we can write that proportional relationship where our total cost is going to be equal to our constant of proportionality, 30, times our number of hours. Number of hours. So let's see which of these choices, and it might be more than one, say this or describe what's going on here.

So choice A, the y-coordinate of point A, so point A is at the point four comma 120, so the y-coordinate is the 120. That's the total cost when you run your business for four hours. The y-coordinate of point A represents the total cost of electricity when the business operates for four hours. Yes, that is exactly or very close (laughs) to what I just said, so I like this one.

The total cost of electricity is $35 when operating the business for one hour. So let's go to one hour here. This is going to be the total cost. Now, you might say, hey, this looks kinda close to $35, but that's why it was useful for us to write this relationship right over here, because what we see is that our total cost is going to be 30 times our number of hours.

Our total cost here is actually going to be 30, not 35. And it actually does look smack dab in between 20 and 40 versus a little bit closer to 40. So this one is not going to be true. And we're not gonna select none of the above, 'cause we actually did select one of the above. And we're done.

More Articles

View All
B2B Startup Metrics | Startup School
[Music] Hi there, my name is Tom Blumfield. I’m a group partner at Y Combinator, and today we’re going to be talking about one of my favorite topics: metrics and why they’re so useful for startups. So why are metrics important? First of all, it’s pretty …
Embracing Nihilism: What do we do when there's nothing?
God is dead. God remains dead, and we have killed him. How shall we comfort ourselves, the murderers of all murderers? What was holiest and mightiest of all that the world has yet owned has bled to death under our knives. Who will wipe this blood off of u…
To everyone that says “Spend your money NOW! You might not be alive tomorrow!”
You don’t need money and things to be fulfilled because once you escape that mindset, you realize that there is no price to happiness because it was free all along. What’s up, you guys? It’s Graham here. So, gonna go a little bit more personal and maybe …
The Moment That Broke His Memory | The Long Road Home 360
[Music] I don’t think I’ve been just Carl since that day. PTSD to me is not a disorder; that is a reasonable reaction to something traumatic that you have been through. [Music] Looking back, we were also green; we had no idea what we were doing. SolarC…
Deadly Conservation | Explorer
[Music] There are a multitude of issues that are impacting Barunga, 4 million people living just a day’s walk away from the park’s border, and those people have nothing but nature to rely on. So that obviously puts an enormous amount of pressure on the pa…
Surviving a Pathet Lao Prison | No Man Left Behind
Unassisted, Vietnam cannot produce the military formations essential to it. News is just breaking: a United States plane has been shot down over [Music] La. When they caught me, I took everything [Music] away, but you’ve got something that they can’t get…