Expert: Ahmed Salami - 11/1/2010

Question
Hello:

I have seen proportions expressed as follows:

a is to b as c is to d, as in a/b = c/d.

Example: 2/4 = 3/6

Is the reason for the explanation as follows?

2 is to 4 as 3 is to 6 because 2 is one-half of 4 and 3 is one-half of six?

Would it be correct to express the proportion as 4 is to 2 as 6 is to 3 because 4 is two times 2 and 6 is two times 3?
even though the proportion is expressed as 2/4 = 3/6, or would the proportion need to be 4/2 = 6/3?

I thank you for your reply.


Answer
Hi Kenneth,
Yes. 2 is to 4 as 3 is to 6 because 2 is one-half of 4 and 3 is one-half of six. Also, 4 is to 2 as 6 is to 3 because 4 is two times 2 and 6 is two times 3.
Proportion is all about comparing ratios.
So, 2/4 = 3/6 and 4/2 = 6/3 are both equally valid proportional statements.

Regards