Please consider the attached graph of circle O.
We have been given that angle C is inscribed in circle O. AB is diameter of circle O. We are asked to find the measure of angle B.
We can see that angle C is inscribed angle of diameter AB. We know that an inscribed angle whose endpoints are a diameter is a right angle. So measure of angle C will be 90 degrees.
We also know that all angles of a triangle add up-to 180 degrees, so we can set an equation as:
![\angle A+\angle B+\angle C=180^(\circ)](https://img.qammunity.org/2021/formulas/mathematics/high-school/zx0bclt29vsxb8p5j9oyzc521tanir8dvq.png)
![46^(\circ)+\angle B+90^(\circ)=180^(\circ)](https://img.qammunity.org/2021/formulas/mathematics/high-school/r0aq2gkdzhb77ui0sarfmsg822w8fy9za5.png)
![\angle B+136^(\circ)=180^(\circ)](https://img.qammunity.org/2021/formulas/mathematics/high-school/b598y462r0gy5uc3q3hwlj5uijzxr5duzr.png)
![\angle B+136^(\circ)-136^(\circ)=180^(\circ)-136^(\circ)](https://img.qammunity.org/2021/formulas/mathematics/high-school/9gr80dksozm7gtan7zouu0v1pav9v9xsze.png)
![\angle B=44^(\circ)](https://img.qammunity.org/2021/formulas/mathematics/high-school/9ug4402hf2gabk2h5ymhb9ymuj6etcn6h1.png)
Therefore, the measure of angle B is 44 degrees.