Explanation:
You need to find one of the following proves:
- SSS (side, side, side)
- SAS (side, angle, side)
- ASA (angle, side, angle)
1) The firs one is mentioned - ∡MRQ = ∡NQR
2) QR is common for both triangles
3) PQ = PR -> that means triangle is equilateral and angles ∡PQR = ∡QRP
Now you now 2 angles and 1 side are the same.
Using ASA (angle, side, angle) that's prove both triangles are congruent.