Answer:
I believe it is 75
Explanation:
The total sum of the shape is 360 and since we know that one of them is 60 we can subtract 60 from 360 leaving you with 300. Now with 4 points left you need to divide 300 by 4, which would give you 75. If you want to check, you can do 75x4+60 which should be 360 :)