Answer:
49 +80= 129
180 - 129= 51
Opposite are equal.
Extend line of QR - so, the x shape made can be used to calculate what x is.
51 + 51 = 102
Reflex angles adds to 360
360-102= 258 of the other opposite angles left.
258/2 = 129 since opposite angles are equal.
Answer is 129 degrees
Hope this helps!