Question

Which of the following is a correct proportion?

Answer 1

First, we'll solve A.

2 x2 = 4

3 x2 = 9

3x2=6, not 9.

So it is not A.

5 x2 = 10

7 x2 = 11

7x2=14, not 11.

So B. is out too.

It isn't D. because 12/9 is improper and 3/4 isn't.

So C. is left.

4 x2 = 8

6 x2 = 12

hope it helps!

Answer 2

Answer: Choice C

4/6 = 8/12

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Explanation:

Let's go through the answer choices

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Choice A.

Assume that the given equation here is correct. If so, then we can cross multiply to get

2/3 = 4/9

2*9 = 3*4

18 = 12

The last equation is false, so the first equation is also false. Choice A is not the answer.

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Choice B.

We could do the similar trick as with choice A, but I'll use another method.

Use your calculator to find that

5/7 = 0.714 approx

10/11 = 0.909 approx

We get different decimal values for each fraction, so there's no way the two sides are the same. Choice B is crossed off the list.

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Choice C.

I'll use another method here. Note how the denominators are 6 and 12, and how 6*2 = 12. If we multiply top and bottom of 4/6 by 2, then

(4/6)*(2/2) = (4*2)/(6*2) = 8/12

meaning that 4/6 = 8/12 is a true equation. We can see it through cross multiplication

4/6 = 8/12

4*12 = 6*8

48 = 48

or we could use our calculator to find that

4/6 = 0.667 approx

8/12 = 0.667 approx

Another calculator trick you can use is type in "4/6 - 8/12" without quotes and you should get 0 (or very close to it) as a result. This is using the idea that if x = y, then x-y = 0.

Choice C is the answer

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Choice D.

Since we found the answer, we technically don't need to check choice D. But let's do so anyway.

Right off the bat, we know that 3/4 is less than one, while 12/9 is greater than one. So there's no way 3/4 = 12/9 could be true.