1) The arc AC has a measure that is supplementary of the measure of arc BC.
The measure of arc BC is 50°.
Then, we can calculate the measure of arc AC as:
[tex]\begin{gathered} m\overarc{AC}+m\overarc{BC}=180\degree \\ m\overarc{AC}+50\degree=180\degree \\ m\overarc{AC}=180-50 \\ m\overarc{AC}=130\degree \end{gathered}[/tex]Answer: the measure of arc AC is 130°