## Finding constant of proportionality [closed]

If a is proportional to b and also proportional to c, why does it make sense to multiply b and c and work from there to find the k?

I also notice if you find the constants individually, and combine them, you get a^2 - why?

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Sorry but this is not the right place to ask this. If you are taking a class, I suggest you ask a classmate or your teacher. – Deane Yang Oct 6 2011 at 1:14