Answer: I think it is b
Explanation:
The circumcenter is also center of the triangles circumcircle. i'm not 100% but if this is one of your answers then i hoped this helped!
1st angle = 2 * 2nd angle
3rd angle = 2nd angle + 80
1st angle = 2x
2nd angle = x
3rd angle = 80 + x
2x + x + 80 + x = 180
4x = 100
x = 25
1st angle = 50
2nd angle = 25
3rd angle = 105
65+70=135
180-135=45
(x+2)=45
x=43
