Alright, so a circle is 360 degrees. We know there's an arc of 90 and an angle extending from the radius being 125.
Since the given angle extending from the radius is at the radius, there will also be a 125 degree arc at the circumference of the circle there.
With this, do:
360-90-125 = 145
to get the amount of arc in the unknown area.
Still though, we need to find the x value, so get the unknown value and set it equal to 145.
16x + 1 = 145
16x + 1-1 = 145-1
16x=145
x = 9.0625 or 9 1/16
Hope that helps.
