Nope, the answer is three. Mean means the average of all the numbers. So all you have to do is to add the numbers up and divide the the amount of numbers with your sum.
The answer is: [A]: ∡PQT and ∡TQS ; since this pair of angle add up to exactly 90°, AND form a right angle (90° angle).
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Supplementary Angles: 180-83, so the answer would be A) 97
PQ Line Segment: You would just have to get a ruler and measure it. From the looks of it, EF looks like the answer
