Examining the given diagram, we can see that QT=ST. According to the Converse of the Perpendicular Bisector Theorem, if a point is equidistant from the endpoints of a segment, then it lies on the perpendicular bisector of the segment. Therefore, T lies on the perpendicular bisector of QS.
We can see that the point R also lies on the perpendicular bisector. This means that it is also equidistant from the endpoints Q and S.
Note that, we already know that the distance to S is 1.3. Therefore, QR=1.3.
