What is the missing reason in the proof? Statements Reasons 1. line segment ST is the perpendicular bisector of line segment RV 1. given 2. angle STR and angle STV are right angles. 2. def. of perpendicular bisector 3. line segment RS is congruent to line segment VS 3. ? 4. line segment ST is congruent to line segment ST 4 reflexive property 5. triangle RST is congruent to triangle VST 5. HL theorem