Alright, lets get started.
Please take a look to the diagram I have attached.
The base side is ON
The terminal side is MN.
We could say angle MNO as angle N.
We could day it as angle ONM also.
So, the answer is ∠ N and ∠ONM. : Answer
Hope it will help :)
Step-by-step explanation:

If you do 27-12 (which is 15) you add 15 to 13 and 20