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82
The sum of the three angles is 180. One is given and the other we can figure out because it forms a straight line (180) with the angle to the left outside. The outside angle is 117, so 180-117 is 63.
So then add up the 3 angles in the triangle
63+35+y=180
y= 82

C. cos 90 = 0 you can see this in the unit circle