The question is asking you to find the measure of YZ's arc.
The arc of a circle is found by finding the central angle. In this case, that's angle YCZ. Remember that a circle's total degrees is 360. Since the angle that you are trying to find is 16% of the circle, you need to find 16% of 360.
For a y-intercept, set in your equation. Remember that a y-intercept intercepts the y-axis, which is found at . Thus, setting will give you the place where your equation intercepts the y-axis.
For an x-intercept, do the opposite, set . This is because the x-axis is found at . Similar to the y-intercept, this will find you the point where your equation intercepts the x-axis.