The lengths of two parallel chords of a circle are 6 cm and 8 cm. If the smaller chord is at distance 4 cm from the centre, what is the distance of the other chord from the centre?
Let AB and CD be two parallel chords in a circle centered at O
Join OB and OD
Distance of the smaller chord AB from the centre of the circle = 4cm
OM = 4cm
MB = 
= 
In ΔOMB,
OM2 + MB2 = OB2
(4)2 + 
2 = OB2
16 + 9 = OB2
OB = 5cm
In ΔOND,
ON2 + ND2 = OD2
(ON)2 + 
2 = 52
(ON)2= 9
ON = 3 cm
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