Answer:
59°
Explanation:
First we find the value of
remembering that the angle that is formed in a straight line (in the diameter of the circle) is 180 °, so the sum :

must be equal to 180°:

and we add the two terms with w:

we move the +4 in the left as a -4 to the right side:

and next we divide by 16:

And now that we know the value of
, we can find the measure of the arc YZ:

substituting


The measure of YZ is 59°