So; Angle B= angle c

Because again; PB=QC QB=RC

So; Triangle PBQ=QCR

...BQ=CQ

... triangle ABQ= triangle AQC

...PQ=RQ

So the triangle PRQ is an isosceles triangle.

...AB-QC=AP AC-BQ=AR，AB=AC。

...QC=QB AP=AR

It can be seen that P Q R is the vertical average line of AB BC AC.

From the above we can see that PR//BC.

So q is also vertically bisecting PR.