Answer:

Explanation:
The complete exercise is attached.
For this exercise it is important to remember that, by definition, if an angle formed by two intersecting chords has its vertex on a circle, this is called an "Inscribed angle".
The following formula is used to calculate the measure of an Inscribed angle:

You can identify in the figure that:

Then you can substitute values into the formula and solve for "x":

Then, AC is:
