ANSWER:
c. 133°
Explanation:
We have that there is a chord that divides the circle in two equal parts because it passes through the middle of the circle. Since it is half of the circle, the arc is 180°, we can see that this arc is the sum of the angles a + b, this angle must measure half of 180°, therefore:
![a\degree+b\degree=(180\degree)/(2)=90\degree](https://img.qammunity.org/2023/formulas/mathematics/college/oaer3egulg1r65mzszbuc78jr403e5swvu.png)
Now the angle c° must measure half of the 86° arc, therefore:
![\begin{gathered} c\degree=(86\degree)/(2)=43\degree \\ \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/7amq01mwhbyspbq7xx5uwhcszzdzlcfnsk.png)
That means that a° + b° + c° is equal to:
![a°+b°+c°=90+43=133\degree](https://img.qammunity.org/2023/formulas/mathematics/college/csxwqpzcca90wlirtuxww1whdg8jthpsqn.png)
Therefore, the correct answer is c. 133°