chemistry
posted by Blaze .
Hi in this question
A typical intravenous dose of I125 for a thyroid diagnostic test is 100 Ci. What is this dosage in megabecquerels (MBq)? (3.7 x 1010 Bq = 1 Ci)
my book solved it like this:
100 u Ci * 1Ci/1x10^6uCi * 3.7x10^10/1Ci * 1MBg/1 x 10^6 Bq = 3.7 MBq. My question is where did the 1 x 10^6 u Ci come from?

1 Ci = 1E6 microCi
1 meter = 1E6 micrometers.