


1) BC = PQ  1) Given  
2) OP = AB  2) Radius of a circle  
3) OQ = AC  3) Radius of a circle  
4) ΔPOQ = ΔBAC  4) SSS Postulate  
5) ∠POQ = ∠BAC  5) CPCTC  



1) OP = OQ  1) Radii of the same circle.  
2) OM = OM  2) Reflexive (common)  
3) ∠OMP = ∠OMQ  3) Each 90^{0}  
4) ΔPMO = ΔQMO  4) HL postulate(RHS)  
5) PM = MQ  5) CPCTC  



1) AB = AC  1) Given  
2) ∠BAM = ∠CAM  2) Given  
3) AM = AM  3) Reflexive (Common)  
4) ΔBAM = ΔCAM  4) SAS Postulate  
5) BM = CM and ∠BMA = ∠CMA  5) CPCTC  
6) ∠BMA + ∠CMA = 90^{0}  6) Linear pair angles  
7) AM = BM and ∠BMA = ∠CMA = 90^{0}  7) From (6)  
8) AM is the perpendicular bisector of BC  8) Definition of perpendicular bisector.  
9) AM passes through the center O.  9) Perpendicular bisector of a chord always passes through the center.  