In triangle PQRPQRPQR, PQ⃗=3i−4j+12k\vec{PQ} = 3\mathbf{i} - 4\mathbf{j} + 12\mathbf{k}PQ=3i−4j+12k, PR⃗=5i+2j−k\vec{PR} = 5\mathbf{i} + 2\mathbf{j} - \mathbf{k}PR=5i+2j−k
Find the vector QR⃗\vec{QR}QR
Find the length of the line PQPQPQ