need help with this question im stuck

Answer:
answer is B. 100°
Step-by-step explanation:
if correct please I need brainlist
Answer:
100°
Step-by-step explanation:
Opposite angles of a quadrilateral inscribed in a circle are supplementary, i.e., they add up to 180°.
The 80° angle and angle x are opposite each other, so:
x + 80° = 180°
x = 180° - 80°
x = 100°