Answers

2016-03-17T08:32:44+05:30
Chord of larger circle will be the tangent to smaller. using this property we get that b is perpendicular to chord cd and bisects it. using pythagoras theorem the length if chord is 2times root of a^2 -b^2
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2016-03-17T08:50:10+05:30
Angle OEC=90(tangent and radius at point of contact are perpendicular)

by Pythagoras theorem
OC^2=OE^2+CE^2
a^2=b^2+CE^2
√(a^2-b^2)=CE
CD=2CE[perpendicular drawn from centre bisect the chord]
CD=2√(a^2-b^2)
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