Lets say I have two hexadecimal values:

185A39
A5BDB5

Those represent hex colors.

Now, I define another two-set pair. The first value is:

31ABE1

I need to obtain the second value.

The first pair is what I need to base my formula on. So, I thought I would use the rule of three to obtain the second value of the second pair.

So, I did:

? 0x185A39/0xA5BDB5*0x31ABE1

I obtain 478298.07. This is decimal. I then need to put that into hexadecimal value. I found a program on the net and this gives 0x00077361. This does not seem to be the value I am looking for. Anyone would know the best approach to do that?