Answer:
QR is the side corresponds to side NO.
Step-by-step explanation:
SSS(Side-Side-Side) Postulates states that if three sides of one triangle are congruent to three sides of another triangle, then the two triangles are congruent.
Given: Side MN= 6 units , OM = 9 units , PQ = 6 units and RP = 9.
In triangle MNO and triangle PQR
MN = PQ = 6 units            [Side]
OM = RP = 9 units.           [Side]
NO = QR                           [Side]
Then; by SSS postulates 

Therefore, the sides which corresponds to side NO is, QR .