Answer:
I hope I'm thinking about this correctly, because I'm only 90% sure right now.
The answer is 18.73 meters.
Explanation:
1) The shadow is longer (of course), and you are finding the proportion of the object's height to its shadow.
2) In your calculator, type 2.7/1.6; this will give you the proportion in a number.
3) Take that number (which is approx. 1.69 m), and multiply it by the height of the building.
4) 11.1 x 1.69 = 18.76 meters or 18.73 meters, depending on how you round.
If this wasn't clear, please let me know and I'll try to explain it differently.