# a bit stuck with ratios

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#1
hi im kinda confused how i would put this in ratio form CD = (-3/2) AB

AB:CD
-3/2 : 1

sorry i just cant remember what id do
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1 month ago
#2
(Original post by anonymous230)
hi im kinda confused how i would put this in ratio form CD = (-3/2) AB

AB:CD
-3/2 : 1

sorry i just cant remember what id do
AB and CD are lengths so no negative sign.
also ratios are usually expressed in terms of integers.

You have the fraction
CD = 3/2AN
So multiply through to get integers and write as a ratio.
Last edited by mqb2766; 1 month ago
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#3
(Original post by mqb2766)
AB and CD are lengths so no negative sign.
also ratios are usually expressed in terms of integers.

You have the fraction
CD = 3/2AN
So multiply through to get integers and write as a ratio.
CD = 3/2 AB

2 CD = 3 AB

so would it be CD:AB = 2:3

im not sure how they got CD:AB = 3:2
0
1 month ago
#4
(Original post by anonymous230)
CD = 3/2 AB

2 CD = 3 AB

so would it be CD:AB = 2:3

im not sure how they got CD:AB = 3:2
It's always like that. Of the total length.
CD is 3/5
AB is 2/5
So the ratio CD:AB is 3:2.

I find it easier to think in terms of fractions to get it the right way round.
Last edited by mqb2766; 1 month ago
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#5
(Original post by mqb2766)
It's always like that. Of the total length.
CD is 3/5
AB is 2/5
So the ratio CD:AB is 3:2.

I find it easier to think in terms of fractions to get it the right way round.
but CD would be 2/5 not 3/5?
i get the 2:3 thing but i get it swapped around
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1 month ago
#6
(Original post by anonymous230)
but CD would be 2/5 not 3/5?
i get the 2:3 thing but i get it swapped around
No CD is larger than AB as it's multiplied by 3/2.
Just remember it's the opposite way from what you first think.
Last edited by mqb2766; 1 month ago
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1 month ago
#7
If you are still not sure how to work out CD:AB
from 2CD = 3AB you could try replacing CD and AB with numbers that hold the equation true.
For example let CD = 6 and AB = 4.
It is true 2 × 6 = 3 × 4
Can you express 6:4 as a simpler ratio? (this is equivalent to ratio CD:AB)
If you are ever not sure if your answer is correct just plug in some numbers to check.
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#8
(Original post by hoosie)
If you are still not sure how to work out CD:AB
from 2CD = 3AB you could try replacing CD and AB with numbers that hold the equation true.
For example let CD = 6 and AB = 4.
It is true 2 × 6 = 3 × 4
Can you express 6:4 as a simpler ratio? (this is equivalent to ratio CD:AB)
If you are ever not sure if your answer is correct just plug in some numbers to check.
thank you very much it became much clearer after i replaced it with numbers!

(Original post by mqb2766)
No CD is larger than AB as it's multiplied by 3/2.
Just remember it's the opposite way from what you first think.
yehh i see now , thanks!
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