Answer: 51.1 degrees
Explanation:
If some angle x is supplementary to [tex]128.9^{\circ}[/tex], then we can say the following:
[tex]x+128.9 = 180\\\\x = 180-128.9\\\\x = 51.1\\\\[/tex]
Therefore, the two angles [tex]51.1^{\circ}[/tex] and [tex]128.9^{\circ}[/tex] add to 180 degrees. The two angles can be glued together to form a straight line.
