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 `sqrt(5)\ c m` (b) `2sqrt(5)\ c m` (c) `2\ sqrt(7)\ c m` (d) `sqrt(7)\ c m`
Let `AB` be chord, `OL` is the perpendicular distance.
In right `/_\OAL, OA^2=AL^2+OL^2`
`(6)^2 =(82)^2+OL^2`
`A L=12AB`
`36=16+OL^2`
`OL^2=36−16=20`
`OL =sqrt20=sqrt(4xx5)=2sqrt5 cm`

Explanation

Let `AB` be chord, `OL` is the perpendicular distance.
In right `/_\OAL, OA^2=AL^2+OL^2`
`(6)^2
=(82)^2+OL^2`
`A
L=12AB`
`36=16+OL^2`
`OL^2=36−16=20`
`OL
=sqrt20=sqrt(4xx5)=2sqrt5 cm`