One arc is shown as 110 deg.
The arc intersected by the 90-deg angle measure 90 deg.
110 + 90 = 200
360 - 200 = 160
That means the upper arc is 160 deg.
The angle made between a chord and a tangent is half the measure ofthe arc intersected by the chord.
b = 160/2 = 80
Answer: b = 80
