Answer:
5. 23
6. 26
7. 20
8. 45
9. 15
10. 120
11. 60 full triangle is 180 and since it is equilateral you divide it by 3 you get 60
12. It is not possible. if you use the pyagorean theorem (not sure on spelling of that?) you get 16 so its not possible for it to be 12.