Answer:
x = 127°
Step-by-step explanation:
Let A, B and C be the three angles of a quadrilateral such that they are 55, 73, 105 respectively.
We know that, the sum of angles of a quadrilateral is equal to 360°. Let fourth angle be x.
55+73+105+x = 360
233+x=360
x = 360-233
x = 127°
So, the fourth angle is equal to 127°.