Answer:
ASA congruence and CPCT property
Explanation:
There are two triangles PRQ and SRT given
In these two triangles we have
QR=TR, Angle Q = angle T and angle PRQ = Angle SRT
i.e. two angles and corresponding side are congruent.
Hence by ASA congruence for triangles the two triangles
PRQ and SRT are congruent
By CPCT property for congruent triangles,
we have corresponding sides are equal.
Hence PR = SR
Proved.