Question

If the chord is at distance 3 cm from the centre of a circle having radius 5 cm, then the length of the chord is ______ (a) 4 cm
(b) 6 cm
(c) 8 cm
(d) 10 cm

Answer 1

Apply Pythagoras theorem...

$h {}^{2} = p {}^{2} + b {}^{2}$

$5 {}^{2} = 3 {}^{2} + b {}^{2}$

$b { }^{2} = 25 - 9 = 16$

$b = \sqrt{16} = 4cm$


Total length of chord is 2 × 4cm = 8cm


OPTION C

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