Answer:
b = 80°
Step-by-step explanation:
The inscribed angle measuring 100°, is supplementary to the angle opposite it in the inscribed quadrilateral.
Thus, the angle is = 80°
Therefore, b + 80° = 180° (angle on a straight line = 180°).
Thus, b = 180° - 80° = 100°.
The measure of b is 80°.
