Answer: 28
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Step-by-step explanation:
Angle UOT is vertical to the angle x. This angle combines with 4x and 40 to get a straight angle of 180 degrees
(angle POU) + (angle UOT) + (angle TOS) = 180
4x + x + 40 = 180
5x + 40 = 180
5x = 180-40
5x = 140
x = 140/5
x = 28
Side note: if x = 28, then 4x = 4*28 = 112.
We see that 112+28+40 = 180, which is the sum of the three angles mentioned earlier. Since we got 180, this confirms the answer.