Since RS bisects PQ at point R, then R is the midpoint of PQ.
PQ = 14 given
PR = RQ definition of midpoint
PR + RQ = PQ segment addition postulate
RQ + RQ = PQ substituted PR with RQ
2RQ = PQ simplified (added like terms)
2RQ = 14 substituted PQ with 14
RQ = 7 divided both sides by 2
Answer: 7 cm
