A chord is 2cm from the centre of a circle. If the radius of the circle is 5cm, find the length of the chord

A.

2\(\sqrt{21}\)cm

B.

\(\sqrt{42}\)cm

C.

2\(\sqrt{19}\)cm

D.

\(\sqrt{21}\)cm

Correct answer is A

From \(\bigtriangleup\) OMQ find /MQ/ by Pythagoras OQ2 = OM2 + MQ2

52 = 22 + MQ2

25 = 4 + MQ2

25 - 4 = MQ2

21 - MQ2

MQ2 = 21

MQ2 = \(\sqrt{21}\)

Length of chord = 2 x \(\sqrt{21}\) = 2\(\sqrt{21}\)cm