If PQ = QR, the triangle is isosceles, and we have two equal angles opposite PQ and QR. So we have two 58 degree angles (x = 58), and since the sum of the three angles in a triangle is 180, we can find the third angle y and answer the question.
In a triangle, the longest side is opposite the largest angle, and the shortest side is opposite the smallest angle. So if PR > QR, the angle opposite PR is greater than the angle opposite QR, or in other words, y > x, which is what we wanted to know.
So each Statement is sufficient and the answer is D.
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