1. BD is perpendicular to AC - given
2.BD bisects AC - given
3. <BDC = 90 degrees; < BDA= 90 degrees - definition of perpendicular
4. m<BDC = m<BDA - substitution property
5. m<ABD = m<CBD - definition of a bisector
6. BD = BD - reflexive property
7. ABD = CBD - Angle-side-angle congruency theorem
hope this helps at all
