can someone help me find the value of x?

Answer:
The measure of arc x is [tex]60\°[/tex]
Step-by-step explanation:
we know that
The measurement of the external angle is the semi-difference of the arcs it comprises.
so
In this problem
[tex]55\°=\frac{1}{2}(170\°-x\°)[/tex]
solve for x
[tex]110\°=(170\°-x\°)[/tex]
[tex]x\°=(170\°-110\°)=60\°[/tex]