The side on triangle PQR that corresponds to side LN in triangle MNL is side QR.
Step-by-step explanation:
Triangle PQR is a dilated version of triangle LMN, specifically a dilation of 2, since LN = 12, the corresponding side to it on triangle PQR is side QR because it is twice as big as side LN, which is the dilation value for converting triangle LMN to triangle PQR.