Answer:
128
Explanation:
The sum of angles in the triangle is 180 degrees
12 + 40 + x = 180
52 + x = 180
x= 180 - 52 = 128 degrees
(x is the third angle of the triangle)
Credit: study1104 for the answer: they originally answered this question, though i copy and pasted to help you with your assignment! Hope this helps, wanted to include credit so your aware where the answer came from!!