Answer:
[tex]b = 360 \degree - (2 \times 68 \degree + 104 \degree) \\ = 360 \degree - (136\degree + 104 \degree) \\ = 360 \degree - 240 \degree\\ \: \: \huge \red{ \boxed{\therefore \: b = 120 \degree}}[/tex]
130
Step-by-step explanation:
