Cross multiplication is how you would solve this problem therefore, you multiply the 16 and the 8 which is 128, then you divide 128 by 64 which is 2. Your missing proportion is 2.
I hope this helps!
If you were to line them all up:
number of desks* how long it measures = total measurement
28*26.17
=<span>732.76 inches
</span>
There are 4 15 minute periods in an hour, so you would multiply the 15 minute rate by 4 giving you 12•4. The answer is 48.