question_answer

The radius of a circle is 6 cm. The perpendicular distance from the centre of the circle to the chord which is 8 cm in length is

A)  \[\sqrt{7}\,\,cm\]                       

B)  \[2\sqrt{7}\,\,cm\]

C)  \[2\sqrt{5}\,\,cm\]         

D)  \[\sqrt{5}\,\,cm\]

Correct Answer: C

Solution :

\[AC=BC=4\,cm\] \[OA=6\,cm\] \[\therefore \]\[OC=\sqrt{{{6}^{2}}-{{4}^{2}}}\]             \[=\sqrt{(6+4)(6-4)}\]             \[=\sqrt{10\times 2}=2\sqrt{5}\,cm\]