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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)
• Had it been "Number of days left", it would have been a proportional relationship.
• Why is it not proportional i don't understand this gibberish
• I don't understand how you would find the constant of proportionality. My teacher says that its easy but its not.
(1 vote)
• 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.
• i share a single brain cell with all my brother and sisters... for i am a orange cat. also i havnt had my turn with the brain cell in 10 years.
• 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)
• I understand proportions in other videos (it seems clear and simple to me), but this video confuses me. Any help?