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# Constant of proportionality from tables

Identifying proportionality constants by looking at tables of values.

## Want to join the conversation?

Which table has a proportionality of 3?

A

x y
1 2
2 3
3 4
4 5

B

x y

5 15
6 18
7 21

C

x y

1 5
3 15
5 25

Please upvote this so that others can practice too. If there are any problems, please notify me; I a just a learner like you.

• if I'm allowed to answer its b if not then ill delete this right away
• i hate math. I know that's bad but is it ok even though i work?
• You shouldn't hate math because you think it is hard. Everything is hard when you are learning it. Think about other things you have learned to do that took some time. Believe it or not, math is actually quite easy. If you have the mindset that you are never going to finish something, you never will. You shoulkd stay positive. It's okay to not be perfect at some things, but that doesn't mean that you should give up because it's hard. I like to challenge myself to do things I think is hard. And if we praise students for speed or making things look easy, then the message we are sending them is: I’m only smart when I’m fast or when something is easy. A lot of students say they don’t like math because they are struggling. But you need math to live the rest of your life. If you need help, just ask. That's what Khan Academy was made for.
• How is c not the answer, 2/3 is o.6?
• 2/3 does not equal 0.6
0.6 = 6/10 = 3/5 once reduced.
If you convert 2/3 to a decimal, you will get 0.66666... It is a repeating decimal. You can't truncate the number if you need to maintain the fractions whole value.

Hope this helps.
• Hi! I got a little confused when I went to answer the questions till I figured out a small trick that helped me, especially for the fractions, so I'm going to share it with you guys in hopes it'll help you.

Here's an example, that are like the question you'll do later.
_________

Which table has a constant of proportionality between y and x of 8/5?

A) X | Y
----------
4 | 32/5
10 | 16
11 | 88/5

For the first row simply type "4 x 8/5 =_" now do the calculations and figure out the answer. If the answer is the same as the number next to 4 on the table, then that is the correct answer. (If you type this on a calculator it will most likely show you the answer in decimal form, I just converted the decimal number which was 6.4 into a fraction which was 32/5 the number next to 4 on the table.)

Now to be 100% sure, do the same thing for the rest of the numbers on the table.

So write 10 x 8/5 = _
and calculate that. If it is again, the same as the beside 10 (which is 16) then you are correct!

Now for that last one, write 11 x 8/5 = _ again if it is the same as the number beside 11 on the table (which is 88/5) then you're correct! So A is out correct answer for the whole thing.

You could also do this even if it's not a fraction.
____________________

B) X | Y
----------
2 | 14/5
6 | 42/5
20 | 28/5

Now, to answer this, do the same thing as shown at the beginning of this.

2 x 8/5 = 3.2 (convert to a fraction which is now 16/5)
We can already tell that 16/5 is not the same as the number beside 2 which is 14/5, not 16/5. So we know from that, that 8/5 is NOT the constant proportionality for this table, so B is not the correct answer to our problem.
____________

I hope this helped you guys, please upvote if it did, so others can learn from this🔥 🔥 (this whole thing is probably what Sal did in the video but with different words and more confusing💀💀)
• May we all get 100% on everything.
• Why doesn't it say that I've finished this? Watched it three times!!
• Did you fast forward the video at all? Sometimes it doesn't count the video if you fast-forwarded it.
• once i watch the videos and then i go to a lesson i cant do it can someone help me😅
• I would watch the videos again and more carefully this time. Focus on equations and key words that Mr. Khan says.
• is there an easy way to do these?