Question

PQR is an isosceles triangle in which PQ = PR

M and N are points on PQ and PR such that angle MRQ = angle NQR.
D
Prove that triangles QNR and RMQ are congruent.
R

Answer 1

since we know that PQ and PR are twin sides, well, the angle they each make at the base are also twin angles, Check the picture below.