Step-by-step explanation:
[tex] measure \: of \: interior \: angle \\ = \frac{ (18 - 2) \times 180 \degree}{18} \\ = 16 \times 10 \degree \\ = 160 \degree \\ \\ measure \: of \: exterior \: angle \\ = \frac{360 \degree}{18} = 20 \degree \\ \\ \\ [/tex]
