In the given triangular ruler, \(\triangle ABC\) is similar to \(\triangle PQR\). If \(AB =\) 15 \(cm\), \(BC =\) 18 \(cm\), \(QR =\) 6 \(cm\), \(RP =\) 3 \(cm\), then find the remaining lengths of both the triangles.
1. The length of \(CA\) is \(cm\).
2. The length of \(PQ\) is \(cm\).