Suppose that the two lines that form the missing angle are tangents to the circle. Then, the measure of the missing angle can be found using the following equation:
[tex]\measuredangle ABC=\frac{arc\text{ AEC - arc AGC}}{2}[/tex]
Notice that we can complete the information about the arcs of the circle with the central angle:
then, we can find the angle x with the following expression:
[tex]\begin{gathered} \measuredangle x=\frac{243-117}{2}=\frac{126}{2}=63 \\ \Rightarrow\measuredangle x=63\degree \end{gathered}[/tex]
therefore, the measure of the missing angle is 63 degrees.
