1) QS is perpendicular to PR and PQ=QR (given)
2) QS=QS (reflexive property)
3) Angles PQS and RQS are right angles (perpendicular lines form right angles)
4) [tex]\angle PQS=\angle RQS[/tex] (all right angles are equal)
5) [tex]\triangle PQS \cong \triangle RQS[/tex] (SAS)
