Chords AB and CD of a circle with centre O intersect at a point E. If OE bisects angle AED, then prove that AB = CD.
Draw OM⊥AB and ON⊥CD
In ΔOEM & ΔOEN,
∠OME = ∠ONE = 900 [OM ⊥AB and ON⊥CD]
∠OEM =∠OEN [Given, OE bisect ∠AED]
∠MOE = ∠NOE [when two angles of two Δs are equal, the third angle is also equal]
Also, OE = OE [Common]
OM = ON [C.P.C.T]
Chord AB and CD are equidistant from the centre
Therefore, Chord AB = Chord CD