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### Course: 7th grade>Unit 1

Lesson 3: Identifying proportional relationships

# Proportional relationships: bananas

A proportionality problem about eating bananas.

## Want to join the conversation?

• I have four questions:
.When a problem is not proportional, do we just say it's not proportional and go on to the next question?
.What kind of relationship is it if it's not proportional?

.Could we still solve it even if it's not proportional?
. And why would he waste money on 100 bananas? :)
• 1. Since there's a way to solve nonproportional relationships, you would still solve it (in a graph or a table).
2. Non-proportional :)
3. Yes, assuming the problem still makes sense.
4. Maybe he really likes bananas and they were on sale if you got 100 of them? idk
• When doing the ratios, does it matter which number is the numerator and which is the denominator? For example, is Y always over X?
• It depends on the ratio.

For example if we say the ratio of A to B, then it is A : B, which is A / B.
(1 vote)
• guys the math is not mathing
• then you maybe have to go to class 1

i have some questions for class one

1. what comes after 6__
2. 2+3=_
3. 1-1=_

4.what comes before 10____

hope the math maths now
😂😂😂
• Why is it not proportional i don't understand this gibberish
• It's because it asks the number of days that pass, not the number of bananas Nate has eaten. If it was the latter, then the relationship would be proportional.

Here is an example:

imagine you have 5 apples. You eat one each day. Then, the equation would be like this.

`amount of apples left (x) (-1 per day) = number of days that pass (y) (+1 per day)`

So, it would be proportional.

I hope this helps!
(1 vote)
• I don't understand how you would find the constant of proportionality. My teacher says that its easy but its not.
• Yes, it really is easy. Assuming that you are given a proportional relationship and some ordered pairs, choose any ordered pair with nonzero x-value, and divide the y-value by the x-value in that ordered pair to get the constant of proportionality.

Then check to see if you get the same answer if you do the same thing with another ordered pair. If you don't get the same answer, then either you made a mistake or you were not given a proportional relationship.
• Had it been "Number of days left", it would have been a proportional relationship.
• i dont understand
cant you just divide without ratios?
• well sure but if you use ratios then youre doing it right and if you dont you will be executed so its kinda a lose lose
(1 vote)
• who really understands this?
• I do, it’s not easy to understand but I can.

So we know that the number of bananas eaten are proportional to the amount that Nate has left, so we ask is it proportional to the number of days that have passed? We can divide the amount left (98) by the days passed (1) and we get 98. As Sal says we need to the same for day 2 so 96/2 = 48, that means the amount eaten nor the amount left are proportional to the number of days passed. `96 & 2 are not equal to 48`.
(1 vote)
• I understand proportions in other videos (it seems clear and simple to me), but this video confuses me. Any help?