Given, in triangles, △PQR and △XYZ,
side RP = side ZX = 6cm
∠QRP = ∠YZX = 140°
side QR = side YZ = 9cm
∴ by SAS criterion for congruency of triangles, △PQR ≅△XYZ
So,
∠RQP = ∠ZXY = 25° (corresponding parts)
In triangle, △PQR,
∠PQR = 180° - (∠RQP + ∠QRP)
⇒ ∠PQR = 180° - (25° + 140°)
⇒ ∠PQR = 15°