If two equal chords of a circle intersect, prove that the parts of one chord are separately equal to the parts of the other chord.
Given: Two equal chords of a circle intersect
Let us construct a circle with centre O.
Its two equal chords are AB and CD which intersect at E as shown in the figure.
To prove: AE = DE and CE = BE
Proof:
Draw OM AB and ON CD
Join OE
In OME and ONE,
OM = ON (Equals chords of a circle are equidistant from the centre.)
OE = OE (Common)
OME =ONE (90o)
OME ONE (RHS congruence)
ME = NE (C.P.C.T.) ..…(i)
Now as AB = CD
AM = DN..…(ii)
Adding (i) and (ii)
AM + ME = DN + NE
Þ AE = DE
Also, AB – AE = CD – DE (AB = CD)
BE = CE
Hence proved