We start by putting it over 1:
Now we use the fact that 2.54cm = 1in, and make a unit multiplier
with "cm" on the bottom to cancel out the "cm" in the top, and multiply
by it:


Cancelling the "cm",


Next we use the fact that 12in = 1ft, and make a unit multiplier
with "in" on the bottom to cancel out the "in" in the top, and multiply
by it:




Cancelling the "in",




So all that's left is
or
or
49.21259843 ft
Edwin