- Perpendicular line from the centre to chord bisects chord.
Condition: $ON\perp AB$
Result: $AN=BN$
Reference: $\perp$ line from centre to chord bisects chord
- Line joining the centre to the mid-point of chord is perpendicular to chord.
Condition: $AM=MB$
Result: $OM\perp AB$
Reference: line joining centre and mid-pt of chord $\perp$ chord
- The perpendicular bisector of a chord passes through the centre.
Reference: $\perp$ bisector of chord passes through centre
- For two equal chords, their distances from the centre are equal.
Condition: $AB=CD$
Result: $OM=ON$
Reference: eq. chords equidistant from centre
- For two chords are equidistant from the centre, they are equal in length.
Condition: $OM=ON$
Result: $AB=CD$
Reference: chords equidistant from centre eq.