Answer:67 degrees
Step-by-step explanation:
A quadrilateral is 360 degrees. You have 1 angle. Look at the left and right sides. If they're the same, then the opposite angles are congruent. Since they're congruent, that would mean the angle between 10.4 and 20.8 is 113. Since the angle opposite of x is the same as x, we could solve now. We make an equation
2x+113+113=360
x=67
