Answer:
70°
Step-by-step explanation:
All triangles' angles are added up to 180°
30 + 80 + x = 180
110 + x = 180
x = 180 - 110
x = 70
[tex]x = 70[/tex]
[tex]x = 180 - (30 + 80)[/tex]
[tex]x = 180 - 110[/tex]
to be sure
[tex]70 + 80 + 30 { = }^{?} 180[/tex]
[tex]100 + 80 { = }^{?} 180[/tex]
[tex]180 = 180[/tex]
