This triangle has one side that lies on an extended line segment. Based on this triangle, what statement about x is true?

x = 43 because 71−28=43 and 28 + 43 = 71

x = 81 because 180 − 71 − 28 = 81

x = 99 because 28 + 71 = 99 and 99 − 28 = 71

x = 137 because 180 − 71 + 28 = 109 + 28 = 137