Here's a list of the changes and their effect:
So, the function is shifted 
units to the right, then it is compressed by a factor 8 horizontally, and a factor 0.35 vertically.
C = 2×pi×r
72 = 2×pi×r
so r = 36/pi
DE = 30deg×36/pi
DE = (pi/6)×(36/pi) = 6cm
It would be a variable because it doesn't tell us how much he made. So put a random letter, I would use X.
