Thm 1 Congruent chords have congruent arcs, and congruent arcs have congruent chords.
Thm 2: A diameter that is perpendicular to a chord bisects the chord and its arc.
Thm 3: 2 chords that are equidistant from the center are congruent. The converse is true.
Converse: 2 chords that are congruent are equidistant from the center.