I posted a question, but realized due to my multitasking, completely messed up the question.

My question is Which ratios form a proportion?
A. 4/9, 12/25
B. 3/7, 18/42
C. 5/11,20/45
D. 5/8, 15/25

I don't understand how to find the answer, could someone help?

One way to do this is to set up a proportion and cross multiply.

4/9 = 12/25
108 = 100
Nope

Try the others that way.

So the answer would be B?

Yes, B.

Of course, I can help you understand how to find the answer to your question! To determine which ratios form a proportion, we need to check if the ratios are equivalent. Two ratios are considered equivalent, and therefore form a proportion, if their cross products are equal.

Let's go through each option and find their cross products to see if they are equal:

Option A: The cross products are 4 * 25 = 100 and 9 * 12 = 108. Since 100 is not equal to 108, this ratio does not form a proportion.
Option B: The cross products are 3 * 42 = 126 and 7 * 18 = 126. Since both cross products are equal to 126, this ratio forms a proportion.
Option C: The cross products are 5 * 45 = 225 and 11 * 20 = 220. Since 225 is not equal to 220, this ratio does not form a proportion.
Option D: The cross products are 5 * 25 = 125 and 8 * 15 = 120. Since 125 is not equal to 120, this ratio does not form a proportion.

Therefore, the correct answer is option B (3/7, 18/42) as it forms a proportion since its cross products are equal.