I need help on in the answer to this question

ANSWER:
D. 100
STEP-BY-STEP EXPLANATION:
We can calculate the internal angles since the sum of all of them are equal to 360°, and that the behaved angles are equal, therefore, we can establish the following equation:
[tex]\begin{gathered} 73+73+\alpha+\alpha=360 \\ 2\alpha=360-73-73 \\ \alpha=\frac{214}{2} \\ \alpha=107\text{\degree} \end{gathered}[/tex]We can calculate the value of z, with the help of the following rule:
Therefore, in this case:
[tex]\begin{gathered} \alpha=\frac{1}{2}(z+114) \\ \text{ replacing and solving for z} \\ 107=\frac{1}{2}(z+114) \\ 214=z+114 \\ z=214-114 \\ z=100 \end{gathered}[/tex]The value of z is 100°