Answer:
83 degrees
Explanation:
The exterior angle of a triangle can be find by adding up the two inner angles that are not adjacent, so
43 + x = 126
x = 83 degrees
Second way
exterior angle + inner angle = 180
126 + inner angle = 180
inner angle = 54
the sum of the inner angles of a triangle is 180 degrees
54 + 43 + x = 180
97 + x = 180
x = 83 degrees